1. You'll probably want WP for easy leveling but both should be good.
2. Not any more than Katana, BS, DB ... MA, Spines....
Claws/wp is basically the smoothest, easiest leveling experience there is:
You have your entire attacks chain pretty well sorted by level eight, and have close to zero endurance issues.
It's a fun, easy ride. Even better, with some work, a claw/wp can peak out at a very high level of performance indeed.
A claw/inv is not as easy, although the light-end nature of claws works well with inv. At the top end, inv can be made stunningly durable, considerably more tough than willpower. It's just a bit more work to get there.
The important thing is, have fun! 
Either one will do very well indeed. 
Thank you both for your assistance! I was wondering about durability at end game. With that goal in sight, I'm going to play with Mids a bit more and see if I can achieve "good enough" survivability with the /WP. If not, I'll go the /INV route.
CoV Teams:
"In CoV, its generally more like the Suicide Squad. If you aren't sure who's going to die at the end of this mission, then its probably you."
-Arcanaville
I want to preface this by saying most of my experience is with blasters and MM's. I'm making a new scrapper to try out some of the other story lines in Praetoria and I'm currently torn between claws/inv or claws/wp. I'm looking for the combination that's going to give me a smoother ride to 50. I've taken a spines/regen past 20 and it was fun for a while, but it always seemed I was just avoiding death. It ended up shelved. Claws seems pretty solid, although I wonder if the damage type is going to be heavily resisted later.
So my questions are:
1) Claws/inv or claws/wp for the better leveling experience?
2) Will claw damage be heavily resisted later on?
Thanks in advance.
CoV Teams:
"In CoV, its generally more like the Suicide Squad. If you aren't sure who's going to die at the end of this mission, then its probably you."
-Arcanaville