Last time?... about 4 years ago I guess. Last time I read up on it was in January to find that they're still saying microstuttering is much less evident in triple-GPU setups than dual-GPU setups. Anyway, most games are not programmed to make use of multiple GPUs, making extras wasted. It really does depend on the needs really, and the advice for gaming has always been to get a single, stronger graphics card instead of two weaker graphics cards in SLI/CrossFire.
The ones worth playing are. Every noteworthy game in the past two years has worked just fine for me, with the exception of Assassin's Creed III, which can be maxed out with a single card.
Edit: After looking at that site, they grossly overcharge for 780s, and a lot of the areas where you can cut cost without sacrificing performance don't have any inexpensive options. So, this was all moot since you can't really fit SLI into a $2000 budget if this site is your only option for ordering.