Theater critics only feel secure when they can affect the persona of either the withering cynic (think George Sanders' Addison DeWitt in All About Eve) or the good-hearted, sentimental slob (picture Lassie with a laptop).

The reason for giving thanks this week is Beck Center's local debut of that rarest of commodities, a promising new musical, entitled The Breakup Notebook: The Lesbian Musical. Adding to the triumph is the next step in the burgeoning partnership of director Victoria Bussert and choreographer Martin Cespedes, exquisitely showcased by set designer Russ Borski and exuberantly rendered by an exceptional cast of young and veteran pros.

Before the exclamation-point-drenched panegyrics commence, we'll get the nuts-and-bolts and nitpicking out of the way. As to plot, take Sweet Charity's love-starved dance- hall hostess and update her with a new sexual orientation and a more feminist-approved profession. Still, at heart, our new-age Charity has the same neediness and propensity for madcap encounters on her bumpy road to romance and self-realization. As for the nitpicking, the show is only 75 percent on the way to off-Broadway readiness.

The evening's first 20 minutes are unfocused and scattered, introducing too many characters before giving us the proper song to set up the heroine's dilemma. The other major flaw is an inconsistency of tone. While all the female characters are treated with great compassion, sensitivity and nuance, the single male character is served up as a lisping stereotype right out of Will and Grace.

Now to the hosannas: This is a musical completely free of Sondheim envy. Lori Scarlett's lyrics and music (with additions by David Manning) comprise a deft compendium of light pop, ranging from Spice Girls to Don Ho-ish Hawaiian chants, and all persuasively used to illustrate the characters' wants and desires - including a sure-to-be Top 40 hit, "The Chicks and Dicks Bossa Nova."

Patricia Cotter's book is buoyed by much keen satire of lesbian dating rituals. But its special virtues are its nuggets of human understanding. This particularly applies to how our heroine damages her romantic prospects by putting false expectations on friends and lovers. Especially mature and rewarding is her eventual resolve to find herself before she continues her search for love.

Greatly benefiting this new work is the collaborative synergy of Borski's lesbian take on the works of Roy Lichtenstein, Bussert's propulsive dramatizing of emotional truths, and Cespedes' limitless dance vocabulary. Among an amazingly accomplished cast, Tracee Patterson, giving yet another indelible performance, electrifies as a kind of Marlboro Gal, bringing to life an original character that exceeds the limitations of musical theater. At the peak of comic perfection, Alison Garrigan etches out a nervous lesbian with bisexual pretensions. Jodi Dominick's heroine, in every scene, takes us on a gleeful journey from Diane Keaton neuroticism to Rosie O'Donnell empowerment without a false note.