Hey man hows it going - I've only used the CPR1 and I can tell you that its been perfectly fine for my training, everything is clear and its smaller than some others that Ive seen which is always handy when in the cockpit. The instruction manual is a bit awful but I find that its best to learn your computer by actually trying to work out calculations as if you were going on a flight...
They're the ones that transair etc choose with their packages, I assume this is because its affordable?
Just my opinion with what I've used, I hope this helps!
Ian