Well my insights after having solotanked him both in 10 and 25 man. (both due to sucky OTs dieing)
The dmg is defienately healable even on a tank with far from BIS.
In 10 mans we had zero issues, the only one taking dmg was more or less me, except for the whirly thing ofc.
On 25 there was a whole other matter though, people were failing moving from fires and everything was chaos when it came to dps, we ended up killing him with 4 healers, me and 1 hunter being alive, and we managed to get him from 18% to zero on our own

All in all an easy fight with geared tanks and healers. Dont think its advisable to try and MT him if you arent atleast in ulduar10+EoC gear though, in 25 that is.
Regarding loot we've had the bad luck of only getting 1 pve item, which was holy priest ilvl245 gloves.
Lots of pvp legs dropped though.
Peace