I am not familiar with the others but I have an Ultra Stick 60. The arf came in great condition(aside from needing the coating ironed out a little). I have read posts on RCU about all kinds of modifications that need to be done to this arf to make it flyworthy. I didn't do anything to it and it has performed very well. I put it in a grape vineyard yesterday after running out of fuel and needing to fly about 200 yards into the wind to get over the runway (I flew abot 100 yards). Only mashed the very tip of the leading edge of the wing. 10 minute fix-it. I have seen lots of planes come out of that vineyard, destroyed. Anyway, I'm running an MDS .68, with no problems(except for running out of fuel). It can take up to a Saito 1.00. I think that is when you need to start doing some of the upgrades people have talked about here at RCU. I am considering getting an OS 91FX to put on it. I like the crow option also. Really slows this thing down fast. Hope that helps.