Would you buy a SLI card like the one I want?
Probably not...I'd buy single fastest card on earth with passive cooling and be VERY happy with that.
SLI can be troublesome because it consumes power so much (->generates heat) and although most popular games are compatible (have SLI profiles embedded in the drivers), the majority of games are not taking any advantage from the SLI. I don't think that for example Blitz games would be any faster even if you have SLI.