The Bescherelle is the must-have French verb conjugation book. It is used by French schoolkids so I was surprised when I saw that my French school in Paris used it for its (foreign) students. However, it is really the best verb conjugation book out there. It does not have the flip-to convenience of 501 French verbs, but once you get the hang of it (find your verb in the back, then flip to page with conjugation of model verb belonging to same family), it will become 2nd nature. At first I thought that this was a disadvantage; since you are looking at the conjugation of a model verb and not of the verb itself (unless its the model verb whose conjugation youre looking for), you miss the visual component of memorization that you get with 501 FV, which has the full conjugation of each of its verbs. Since, I have found that this is an ADVANTAGE.
Memorizing the conjugation of each French verb (the 501 approach) is daunting. Memorizing conjugation by family, i.e., associating the conjugation of related verbs, is MUCH EASIER. And unlike 501FV, Bescherelle allows you to find the conjugation of every French verb out there! 501 gives you decent coverage, but once you reach an intermediate level of French, you will find more and more verbs that are NOT in 501FV. I bought a variety of French books for study while I was in France, but left most of these behind when I came back to the States, including 501FV but not the Bescherelle! I take it with me wherever I move, and since its hardcover, it wont die on me anytime soon neither.