For a simple ITB application pretty much any aftermarket will cope just fine, Ive mapped similar on everything from 150 quid of megasquirt to 1500 quid of autronic and it really doesnt matter at all in terms of actual power and power delivery.
Personally I like to try and avoid emerald, ive mapped a couple of dozen cars on it now and got decent enough results, so its not like it doesnt work, on it now but I really hate the interface and anything you do just ends up taking longer than it does on other ecus, although that said if you take it to Dave Walker to map, he will do a really good job for sensible money, so if you arent ever going to map it yourself you dont need to care about the shakey interface.
I normally recomend people buy either Omex 600 or Mtech V4 at the moment for cheaper builds as they are both at the budget end of the market but work very well, I prefer the interface a little on the Mtech and I can get them for a better price and they work really well with the standard renault crank sensor which the Omex doesnt like, so that would be my personal preference for an F4R budget ITB build but there really isnt much between them TBH, and certainly Porkies which I mapped on Omex works very well:
http://www.youtube.com/watch?v=NvneFOUM0kM
Omex has more people familiar with mapping it, so if you arent going to map it yourself, on that basis it would make more sense to go for Omex, unless you already have a mapper in mind, in which case just ask them what they would prefer to use.