Currently using Vipersaga from Team venom. I did temporarily try Sabsa Prime 8.5 and it was very fast and smooth but the usual Sense 4 lags starting appearing very soon after install. Viper Saga does have lags, but less frequently and just "seems" to be more stable. So for me its between this and ICE DS. Although ICE-DS v6 seems to have similar lag issues to Viper Saga so I will stick with Viper. I tried one a couple of tweaked roms with Viper, but in the end i ended up performing a clean install using the standard Viper Kernel with Titanium back to recover the apps and data. This gives me the best performance and batteryl life of any rom so far!
Device: Nexus 4
Rom: CarbonRom Nightly - Halo alpha build.
Kernel: Semaphore, Trinity, Matr1x
Device: Nexus 7
Rom: PA - Halo.
Kernel: M-Kernel a55