Looking at tubeless rims for fairly hard riding, what would you recommend?

819

stans ZTR flows

another vote for 819. Although, get some-one else to build them, they're a PITA.

823

another vote for 819.

have them on both my bikes and after a year are still running straight and true.

stans – piss easy to build (I did one for my 1st ever wheel), v light for width

(not so sure about how strong but you don't seem to get lots of whingeing about them)

819 – I've yet to damage one. Well, apart from hitting a tree, but I can't really blame the rim for that one.

Flow. Really light for the width just flippin' expensive. I'm loving mine.

819s, running them on two of my bikes, been great

819, i looked at a stan's i didn't like the pinning and welding on the rim. looked rustic.

Another one for 819's have given mine a good beating on many a rock garden and they're still running true and not a single scratch/dent on them.