A solid 4. The driver tips have held up well, and a few times I've used them for things other than computers and had to put some force on them, and they've still held up.
Concur. We have a few of these kits too. The one I'm carrying around is so old that the case is failing, I've probably had it 15 years or so. I buy lots of other screwdrivers, too, I just can't stop myself. I love getting quality tools. Frankly, the difference in cost is minimal and it's our profession, dammit - get the best!
This is what I use. Bought a bunch of them a while back. I've had many, many screwdrivers over the years and this one is the best one I've ever had by far:
just recently had to have 2 bits replaced on our kit, the 2 we use the most which are the T4 and P5 (the ones used on macbooks)
which is disappointing considering the "hype" put into how good these kits are meant to be.
Side note on this, as ifixit doesn't have a direct shop in UK i bought them through amazon and it was a weird conversation with ifixit, asking if the kit was rusty (I had sent them a full picture of it and it wasn't), I got the bits replaced in the end but it took just over a month from initially contacting them until the new bits arrived.