From this article in the Ft. Worth Star Telegram:

Had she received any formal musical training, she probably would have ended up playing the piano or violin in Carnegie Hall -- or, even more likely, singing at the Metropolitan Opera, instead of the Grand Ole Opry. Her premature death -- as tragically untimely as Schubert's at 31 and Mozart's at 35 -- deprived the world of musical intelligence, spiritual instinct and ravishing native vocal quality of a sort heard -- at best -- in only a half-dozen or so members of any human generation.... Signs of extraordinary, inborn musical talent are not so readily noticeable to the listener; for example, Cline probably had perfect pitch. She taught herself to play piano by ear the minute she found a keyboard, and recorded snippets of conversations with her band reveal she had extreme sensitivity to pitch variation and key. Beyond that, she brought a sense of intelligence, sincerity and insight to that least intelligent, most shallow and commercial of musical genres, the country-western song.... (I)n a genre fueled by exploitation and self-satire, she never stooped to either. Her exploration of emotion is clean and reeks of honesty. She used the standard country-western twang, but sparingly -- no more frequently than an operatic mezzo-soprano with good sense uses a sob. She turned even mediocre material to gold. But when Cline got hold of a good song, such as Neil Sedaka's Stupid Cupid or Cole Porter's True Love, she approached divinity. The Wayward Wind, at three minutes and 20 seconds, becomes practically an oratorio for a singer used to squeezing a world into two minutes.... Had she found the operatic pathway, Cline would definitely have been a Carmen (mezzo-soprano) and not a Tosca (soprano). Her lower range is always smooth and fluid. When she reaches upward, she's brilliant. And she revels in both ends of the range. Her sexual tension would have been perfect for the Spanish gypsy Carmen, but she would have been equally at home as Rossini's ingenue Rosina in the Barber of Seville -- perhaps even, given the easy flexibility of her voice, in the title role of Rossini's Cenerentola (Cinderella).... San Antonio Rose, another Western classic, becomes a cheerful showcase for gorgeous singing a la Cline; listen for delicious stretched consonants and gentle glissandos.

From this review of a show in the Rocky Mountain News:

Patsy Cline may not have known all about the ways of love, but her voice said otherwise. That rich, womanly alto and the hiccup in her voice spoke of pain suffered and sorrows yet to feel. Maybe that's why her music is a staple for drunk girls in bars born years after her death.

From this review of a show in Denver:

The inherent problem with staging a musical bio tribute is the unavoidable fact no mortal actress could possibly fill Patsy Cline's boots. That's how people like Cline become legends.

From this review of a show in Chattanooga:

Patsy Cline is one of the greatest recording artists country music has ever produced. She had “the voice.” It’s the rare singer who can melt your heart and then restore it again in the space of three or four notes with virtually any song. Today’s crop of female singers – Faith Hill, Shania Twain, Wynnona Judd, the Dixie Chicks et al – need to sit in the back and take notes.

The trouble is they can’t. Patsy is dead. She died almost 40 years ago in a plane crash, and nobody has been quite able to pick up her fallen mantle since. Instead, we now get to go to one of the many nostalgia shows making the rounds.... The irony is that Patsy might not have been able to make it in today’s music scene, which thanks to music videos is more about shaking your booty than vibrating your vocal chords. Patsy could stand in front of a mike, not move, just sing, and cause a riot. She is to country what Janis Joplin is to blues.... Janis, too, died young. In fact, American culture is replete with dead heroes, often the best in their field, who burned brightly and then flared out too soon. Nostalgia, instead of being a quaint time-passer, is an industry. Necrophilia and estate licensing are stalwartly on the march....

Shani Hedden has both the honor and unenviable task of trying to fill Patsy’s shoes. It’s almost an impossible assignment. Even Jessica Lange had the songs dubbed with Patsy’s real voice when she played her in the movie version of her life. Jessica was no fool. No matter how well Hedden can sing, there is a gap if you have heard Patsy do the same songs.

While she should be applauded for her courage in stepping up to the mark and jogging the audience’s collective memory, someone needed to apply a little acting craft to make the role more than just a watered down imitation. As Patsy, the script doesn’t let Hedden do much besides sing, so she really needed to look deeper at what may have allowed Patsy to do what she did besides having fortunate vocal apparatus. There is also the nagging question of why did she have to leave us? Why did her talent have to leave us when we needed and still need it so desperately? Immense talent like that can elevate the entire culture.

From this review of a show in Charlotte:

... Her vocal impersonation of the seminal country singer, who died at 30 in a 1961 plane crash (sic), is remarkable. But it also makes you realize why a violinist pays millions for a Stradivarius. Without the instrument, the music is sometimes going to be all technique. Cline had the instrument. Welch has the wail, the wobble, the yodel and the slide, but those won't carry the diehard Patsy Cline fan through 25 songs.... But, hey, if you're going to an actual honky-tonk, why not listen to Cline herself and that wide-open voice as big, fragrant and fertile as the vast apple orchards in her native Winchester, Va.?

From various NY Times articles over the years come these phrases:

".... Patsy Cline's earthy torchiness...."

".... the voice of Patsy Cline... who average(s) in two and a half to three minutes to perform deft exploratory surgery on cheatin' hearts, seven-year itch and other forms of ruptured rural romance...."

".... the raw, hard-bitten resilience of Patsy Cline...."

".... Patsy Cline (anguished true grit)...."

".... Cline's rich, soul-clutching timbres...."

".... Country singers like Patsy Cline... their pure, deep-voiced insistence of truth which, at exactly the right moment, would crack and quaver and break your heart...."

Folk singer Rosalie Sorrels, in the Boston Globe:

.... It is what she calls a heartfelt tone that first drew her to folk music and that continues to define her craft.

''Edith Piaf had it; Patsy Cline had it; Billie Holiday had it,'' she says. ''It's a tone that people can understand, whether they understand the words or not, a feeling coming right from the heart, very personal. You can hear it in all kinds of music, but more in folk, since people's music is made because they need it, rather than for art's sake or for money's sake. They make it because they have to have it in their lives.'' more

From this review of a show in Florida:

It's a voice that continues to enchant and haunt us, despite its owner's tragically early death. Strong yet pliant, soulful and gritty yet ethereally beautiful, Patsy Cline's extraordinary sound changed country music forever and influenced succeeding generations of artists, from Dolly Parton to k.d. lang.

From a CNN review of a book called We Gotta Get Outta This Place by Gerri Hirshey:

It all begins with Bessie Smith and runs through "Mother" Maybelle Carter and Patsy Cline to Diana Ross, Aretha Franklin and Tina Turner, Patti Smith, Madonna, Bikini Kill, and Janet Jackson, finally arriving at Lauryn Hill and Missy Elliott. It is the bloodline of rock and roll's maternal ancestry. It is anything but a straight line. And yet, all those women it passes through seem to have, at their core, a need to do the same thing. Gerri Hirshey summarizes that inner drive in four words: "Gotta sing. Gotta go."

Boy, can they sing. Girl, can they go.