In reply to elliot.baker:
I've done the 3000s a couple of times before - once hiking it in boots and the second running it (in the pouring rain) in road shoes. Road shoes were actually not quite as bad as you might expect and they were perfect for the jog down to Nant Peris! This weekend I was receeing the route for another go at it and I wore X Talons.
I'm not sure there's a perfect shoe for it all. Ideally you'd have a pretty sticky Roclite or similar for Crib Goch, then on the fairly boggy ground down to the road you'd have some bigger studs, switch to road shoes for the run to Nant Peris, and then on the Glyders either Roclites or X Talons are good. The Carneddau aren't technical and on tired legs a decent amount of cushioning might come in useful.
When I do it in a month's time I'm going to wear X Talons and will have a pair of Roclites sat in the car at the foot of Tryfan in case when I get there I feel like I'm falling apart, which is pretty likely.
The poles question is really interesting. I'd assumed poles would be useless until the Carneddau but having been overtaken by Beth Pascall at the weekend who was carrying poles and then going uphill using them in the Glyders I'm starting to rethink that. But then I'm not one of the world's better mountain runners... maybe there's more to her being rapid than just poles...
On Inov8 durability, it seems to be so hit-and-miss. I've done over 800km in a couple of pairs of Roclites with no issues, and my X Talons have done 600km and the uppers are essentially unworn. Another pair I had a while back though wore out pretty quickly, and the pair of Roclites I've just bought look like they're not going to last long. The problem is if you run as infrequently as me is that once you find a pair that lasts they'll have dropped them by the time you need some more.