In some ways, a tribute band is kind of a gimmick in and of itself, but what actually happens with Lez Zeppelin is more worship than "oh look at us" status. Reportedly, these women put on one hell of a live show, even if most of the material consists of note-for-note reproductions of famous Zeppelin songs.
That's actually the surprising thing about this disc -- it rocks pretty hard, almost as if these women are channeling the spirit of the mighty Zep. Sarah McLellan does an admirable Plant; her voice is deeper than his in some spots, but she handles the catalog with the same sort of swagger and spirit Plant did, instead of the machismo bravado that men try to bring to the role. Listening to her belt out "Since I've Been Lovin' You" is quite an experience. 
Steph Paynes also is a remarkable Jimmy Page disciple; even though little of her stuff is original, copying Page is near impossible, as many guitarists have learned for decades. Lisa Brigantino and Helen Destroy play the parts of John Paul Jones and John Bonham, respectively, and each are both amazing in their own right.
But the problem is that the women are almost too good, at least on record. Six of the eight songs here are very faithful covers, with exactly the same vocal tics and drum patterns. Other than production, there is really no difference between this version of "Whole Lotta Love" and the original, which makes one wonder why they should bother with this one. "The Ocean" and "
Granted, these are excellent songs, so hearing them covered so faithfully is good. With a catalog so familiar, though, listeners expect interesting interpretations, such as Page and Plant gave their own songs on No Quarter: Unplugged. It's easy to admire what the girls do here; not only does a certain amount of risk come with covering this catalog, it takes massive skill to make it sound exceedingly similar to the originals, which are not easy songs to play.
Where Lez Zeppelin breaks from its shtick is in two short original instrumental pieces, "White Sun" and "On The Rocks." The former is a mandolin-led piece sounding a bit like "Bron-Y-Aur Stomp" and is quite good, while "On The Rocks" is the girls' take on what an instrumental rocker on "Physical Graffiti" might have sounded like; its closest comparison is "Custard Pie." Both pieces are very Zeppelin-esque, of course.The version of "Communication Breakdown" is more raw and punky, while "Rock and Roll" is good in any incarnation. In fact, the whole album is good. Zeppelin fans won't regret buying it.
However, they won't listen to it very much either. If Lez Zeppelin injects some variety into its interpretations and writes more originals, they could be the greatest Led Zeppelin tribute band working. As such, though, it's probably worthwhile to catch the live show and only pick Lez Zeppelin up as a souvenir, unless one is a hardcore Zeppelin fan who wants to hear all incarnations of these classic songs.