Although I havn't had experience with the Novak speedo's, from what I have seen it looks like the LRP/Nosram is the better speedo and Novak are the best motors.
I've had an LRP 2007 and Nosram ISTC, both have been run in the BJ4 with no heat problems at all. The LRP was run with just a heatsink and the Nosram with it's built in heatsink + fan.
Motor wise I've only ever had an LRP X11 5.5 in the BJ4 which has been faultless so far and nice and fast too.
In the 2wd I've run an X11 6.5 and borrowed Novak Sintered 6.5 and 7.5's. The LRP was definately faster and felt better to drive, but the Novak was much quieter and smoother.
There were a lot of people having problems with the LRP 6.5's rotors falling apart at Bury, me included which is what points me to try the Novak motors next. I don't understand why LRP are sticking to bonded magnets in the 5.5 and 6.5, sintered are more powerful, run cooler, more reliable and cost less to make
Remember I'm not supported by either LRP/Nosram or Novak so I'd like to think I'm not biased
