Please don't think im sticking up for Emerald or that i know an awful lot about mapping.
But in what way's do the other ECU's mentioned above "perform better" than an Emerald apart from the ease of use for the mapper, which if you like me and take it somewhere to be mapped makes no difference what so ever.

I run an Emerald on my Pug 205(s16) track car, i got the ECU a bit cheaper as i know the chap that installed and services Emeralds rolling road. For the ECU, loom a set of hyabusa bodies off ebay and the mapping by Dave Walker stands me at £800.

My car made 192bhp and i now of quite a few people that have gone the jenvey-dta route and haven't made this power.

Im not saying its down to the ECU but if i had chosen one of the other's mentioned i don't think it would have made anymore power, do you ?