I've been using claw for about a year now.
There are clear advantages for using claw, but I've also found that certain staple techniques with Peach are more difficult to do.
Using claw also seems to be a greater strain on my right hand.
I've met a handful of players that use claw, and I don't think Armada does.
Bladewise has told me that he uses claw for certain situations.
I used to swap to claw mid-game when my tactics changed to more float based combat, then switch back when I was focusing on the ground game. But now I utilize claw exclusively.
I use the side of the first knuckle of my index finger for Y, middle finger for Z, and ring finger for R.
Here is my experience:
Stuff that is easier with claw
- Stationary fairs/bairs in float
- More control of aerial momentum while doing aerials such as retreating fairs or bairs
- Instant FC uairs (fun combos with this)
- Easier to get the fast uair from a jump
- B-moves from float
- DJL dsmash
More difficult with claw
- Wavedashing
- Instant FC bairs and nairs
- Over-reliance on the C-stick for aerials, tends to make my fairs and other aerials come out more slowly.
- Jump-cancel grab
- Chain-grabs
- It's more difficult to get the fastfall timing right after an aerial from float, because it's awkward for me to release Y after initiating the aerial with C-Stick. This results in a lot of botched FC hits on shield, because I'm not getting the fastfall.
I've noticed from watching MacD, most of the benefits of claw are still possible from the normal way of holding the controller. The advantages of stationary fairs and bairs is very subtle. A bair performed with a slight tilt on the control stick, followed by an immediate switch to the other direction to correct momentum & positioning is arguably better in most situations.
In the end, it's personal preference. I enjoy claw, but I do dislike how challenging it is for me to do a short hop float into a quick FC aerial... and it took me forever to develop proficiency at wavedashing this way. I believe playing claw makes developing initial proficiency with Peach more difficult, but in the long run you'll be fine either way.