I've been using VJ JB about 5 month. This is the most stable (in globality) in my opinion. Sometimes i had the phone rebooting alone. Cleaning Cache often was assurance of tranquility.
If you are using Data intensively, i would recomend you EV Kitkat, with Korean radios. My 3G/H works better than fine with it (french network). With VJ it was pretty unstable.
I recently tried to roll back on CM7, which didn't afroid the comparation in therms of lag.
I'm running now on Texasice KK, because of my use data.
About wifi tethering, there are apps on play store that can do the job very well.