Right now I'm playing an Artificer with a houseruled entry into Fleshwarper, with my first Homunculus counting as my Familiar, and I'm loving it. The "size increase" is awesome, especially when it lets you use it as a mount, and it's not hard to turn the thing into a combat brute.
I don't really have much to contribute though, other than that Elemental and Maug grafts rock (four ones I'd definitely consider using each), that Undead and Illithid are also good (three winners each), Dragon grafts are mediocre (two winners), and Yuan-Ti and Construct are best left alone (one winner each). I haven't rated Beholder, Fiendish, Plant, Deathless, or Aboleth. Silthilar are okay but incredibly expensive; they're generally only worthwhile if your DM follows the "New Style" graft rules that limit you to five... but those rules don't work with Fleshwarper in the first place, because "New Style" grafts (anything from Eberron or Races of the Dragon) all require separate feats, and Fleshwarper technically doesn't ever grant you access to them. "Old Style" grafts all worked off of the same feat, but had different special requirements which Fleshwarper gradually lets you bypass. You also weren't limited to only five, or only one type, or only one in an item slot. You can't even apply "New Style" rules to the "Old Style" grafts because many lack associated slots. So yeah, talk to your DM and try to work something out.
