I have a chrony alpha master but I have yet to put it together :D

I have 2 at my shop.
I have a "big red" paintball radar chrono ($350) for paintball and if I am in a hurry I will use it for airsoft works great for that. It usually is about + or - 5 feet from my airsoft one. Which is Mad bull. I haven't had a problem with it at all.

I've used Big Red tons of times, and have had wildly varying results - especially with gas guns. I've gotten huge swings as high as 80fps off the correct value for AEG's, and with GBB's, readings could swing +/-200fps - especially when there are large gas clouds emitted. I do not trust any radar based readings for airsoft use. The rounds are likely too small for them to read properly.