Which model of 1080ti is the best?
I think about palit 1080ti palit super jetstream.
The best 1080 Ti cards are probably the watercooled ones. Both EVGA's SC2 Hybrid and FTW3 Hybrid are alright. There are also cards with full cover blocks out there, if you have a custom loop — at least EVGA, MSI and Zotac sell some. Out of the air cooled ones Palit are pretty good, although I don't think they're the best. Asus Strix seems to be a good one. The 3-fan FTW3 is pretty good. I don't like the 2-fan EVGAs (got the regular SC2), their cooling is not very good. MSI Gaming cards seem to generally receive good reviews, but I don't have any experience with them. Aorus should be alright (only have a regular 1080 Aorus Xtreme personally, which is a pretty good card, but looking at the reviews they seem to have a slightly beefier cooler on Ti cards).
Is there any better? Having more hash per Watt?
Hash per Watt is a tricky thing with 1080 Ti. With 1070s, for example, the reference cards had higher H/w than many non-reference ones. Especially noticeable with EVGA SC cards which used the reference PCB but put their better ACX cooler on it, so best of both worlds (except the VRM's were pretty hot, especially before they started to use a gazillion of thermal pads on each card). With 1080 Ti the reference PCB cards might be more power efficient as well (not sure about it), but the reference nvidia's cooler sucks and I'm not aware of any of the vendors' cards using the ref PCB with a custom cooler. So, I suppose I actually have no idea which ones are better in terms of H/W.
I'd guess the "beefier" cards are less power efficient. Will soon have an FTW3 Hybrid and will try to compare it with the SC2 to check this theory of mine.