Glitching like someone else mentioned is normally caused by graphite touching the rx wire, what you can do to stop this even if your wire isn't touching is wrap the exposed wire in either heat shrink (unshrunk) or in fuel line. Any metal to metal contact will cause your system to go crazy as well. Use plastic washers any place you can, or find a way to avoid any metal to metal contact. If you do it right, you will not glitch.
I have run crystal based systems, (M8), and also run synthesized,(XS3 PRO), never had glitching as long as you arew careful how everything is routed in your car or are paying attention to the linkages and metal to metal contacts. The synthesized is very nice and convenient to use. I never had a problem in many months of running my PRO in a drake truck with huge amounts of vibration and big jumps that I used to take at the track. Never a single problem.
All three of the radios that you mentioned are Spektrum compatible as of just a few weeks ago. The 3PK from what I hear is more geared toward someone with bigger hands. However the functions and gizmos on that thing are amazing.
The M8 is also a great radio and many pros around the world and tons of club racers have it as their radio of choice. The M8 is what I run now and after using it a while I find myself looking to trade it for a Helios.
Find what feels comfortable to you, and what you can afford. They all are great radios and you will not be disappointed with any of them.