IMO the best ecu for most people to use on the 20vt is the OE ecu if that option is avalible. you don't need clocks or keys just to have the ecu cracked whitch isn't that dear and the rest is pritty straight forward.
I have a lot of time for megasquirt, aviod the fake ms from Mtec and got for the B&G one MS2 is massively flexible and is one of the best value ecu's out there in terms of what it can do v's cost, there are a few cheeper ecu's about ( have a sout african thing here thats on the market for less than £130 ) but they are very inflexible and slow and not much use for anything other than old donkey v8's