is the reader's guide to Thomas Pynchon's "V" worth it?

Pynchon’s “V” has always struck as one of those books that probably has a hell of a lot more going on beneath the surface than I realize; it’s the most straightforward and normal of Pynchon’s novels, and though the story and characters are interesting it always seems to lack the hardcore wackiness and heaps of allusions of “The Crying of Lot 49” and “Gravity’s Rainbow.” Yet, “V” is as critically lauded as those books, which makes me want to dig deeper into it and find out what I’m missing.

I’ve seen “A Companion to V” in several bookstores and wondered if it was worth it; it’s more expensive than an actual copy of “V,” but promises to fill me in on all the allusions and references that are probably whooshing right over my head.

Has anyone read it? Is it worth it?