we do just about every different ecu so im unbiased and although every second post above says nistune i beg to differ in this case even though they are extremely good (and we are a listed installer of nistune) they are no match for a good well tuned stand alone like the haltech platinum range if you have the budget and plan to do bigger mods down the track, the tuning resolution on a remap is about 50% of that of a stand alone. To make the most of the remap you really need to have a clear plan of future mods.
There are exceptions as we have a few cars now with nistune remaps making well over 350kw's some ecu's are better than others too, i find r31, vlt and ca18's to be less receptive to big mods, whereas zeds, GTR's and 34gtt's and stageas respond well.
The platinum is worlds better than the earlier haltech stuff mainly due to the new interface software, it is one of the best tuning suites around.