We are running brushless in Xray and RDX right now with great luck. Now that I have a good setup on the xray I doubt I'll touch it much all winter. Maybe just minor tweaks for changing track conditions.
Brushless is definately a lot of fun if you have some good competition at your track running brushless. I haven't touched my 4300 brushless motor (other than to change my pinion when the tires got smaller) for like 20 packs now. We have also found that the 4300 is extremely close to the level of speed we are getting out of our 19t motors. We run them together sometimes.
The JRX-s is a bit tight on space for the brushless ESC right now. When the new novak comes out it should work just fine.
The hot shoe at our track with a JRX-s is having some issues with the chassis getting tweaked on hard hits but other than that he loves it.
I think you'll be happy with any of those. Let me know what you decide on ... so I can tease you if it's not an Xray
Since Surge carries Ceramic bearings for the Xray shouldn't that encourage you to go that route?