Doh, beat me to it Paul!
I went with the FMS (crane) roller rockers because I happened upon a very good deal. The Yella Terra product is a very good one. Also I'd put complete confidence in their after sales service. I've installed some of their roller rockers in a commodore and we had some troubles finding the zero-lash point. We actually received a call from one of YT's (design?) engineers to discuss the concern and suggest options. I can't comment on FMS after sales support as my rockers went in like a dream My only criticism of YT is that they provide a "one instruction sheet applies to all" instruction sheet with their rockers and in the case of the stealth series, it doesn't apply to all.
I bought a set of ??? off my local speedshop after he talked me into it, reckoned he never had a problem with em, used to run em on all his boat engines he said. Well they looked allright so I bought em, they then fell to bits over the next couple of months. I don't buy stuff off him anymore, the prick.
Went and bought some YT's, they bolted on my clevo heads not a prob, simple. They've got a lifetime warranty, if one breaks you can buy singles, or part's. I believe you can't do this with cranes.
I haven't even had to adjust them yet.
Just beware of cheap (gold anodized, hint, hint) R/R's you may save $100 but it'll cost ya!