I personally feel that x11 will be the next Scrypt (NOT Scrypt-N or Scrypt-Jane), and as such have been banking a lot of coins - mined a ton of DarkCoin early and sold it for a VERY high profit at $2.8 (mined around 5k of 'em before it hit that high), and have been slowly accumulating HiroCoin since it's still in double-digit difficulty levels.
The mining applications for x11 are not currently as optimized as they could be, but even with that the hash rate is still more than double Scrypt instead of the half you see using Scrypt-N. It's currently only 3.5x-4x faster than a CPU, and doesn't truly push the card to it's limits - this is due to the fact that it's wrapping 11 different algorithms into the calculations as an ASIC-preventative method.. instead of SHA-256, or Scrypt, or Scrypt-N, or Scrypt-Jane, x11 uses blake, bmw, groestl, jh, keccak, skein, luffa, cubehash, shavite, simd, echo in sequence. Due to it not pushing the card to the max, it runs pretty cool temperatures (roughly 40-60% fan for me @ 72C) and uses about 60% less power than Scrypt does allowing you to build systems with one less PSU (a single 1300w PSU can run 6x R9 290x's on a x11 rig, as opposed to the bare minimum of 2000w for Scrypt).
For example, using a single R9 290X at absolute optimal settings:
Scrypt: 990khash @ 350w
Scrypt-N: 460-480khash @ 375w
x11: 2500khash @ 150w
Some speculate that there is a "private" x11 build of cgminer that unleashes it's true potential and runs around 5000mhash per R9 290X. I'd hesitate to believe this is true, personally. People complaining about it's "efficiency" vs. CPU's also miss the obvious points that it's far more than efficient enough - even with x11 only being about 3.5-4x faster than a CPU, it's still far more power efficient, if you say compare a R9 290X to a X990 Extreme using x11 you get the following:
R9 290X: 2500khash @ 150w
Intel i7 X990 @ 3.47GHz: 69khash per thread x 12 = 828mhash @ 130w