i like my AGX. no problems yet. but, I bought from shox.com, so I don't expect any problems if I need warranty work.

my recommendation...
something hard-as-a-rock and adjustable in the back, something harder-than-stock, but not necessarily adjustable in the front. You need the back ones stiff to handle weight transfer off the line. The fronts can be a little mushier (less costly).
my setup is KYB AGX 8-way adjustables in the back, KYB GR2 in the front.