I'm pretty sure I'll just go with the higher quality MSR bottles. Reusing pre-mix bottles would work fine I'm sure, but like evo points out, they just won't be as tough.
"Won't be as tough ....." ? ? ?
I agree that the ready made hole on the MSR cap is a BIG advantage for the climbing application.
But accidentally drop an Aluminium MSR bottle from a tree Vs a Trufuel Steel container .................... ?