I haven't heard of any problems with them.

However, I have some reservations. The plastic back covers on the LA line have proven to be prone to cracking or leaking over the long haul. The plastic needle valve assemblies on the LA's have also been problem spots for some folks. I don't know if they improved those parts for the AX. I hope so. So far, I haven't heard of any having problems, so that's a good sign.

I also don't like that the head is held on by just 4 bolts instead of 6. Again, I've not seen any leak around the head, but it's something to watch for.

Personally, I'd have paied an extra few bucks for metal parts. But that's just me.