There are pros and cons for each system, I have heard of people in the USA having burnt out ECUs with APR, and people having problems with REVO, none are perfect.
I don't have a CAI, but have replaced my filter with a Pipercross filter in the standard airbox, a REVO Stage 2 pipe (between the air box and the turbo) also fitted the Forge boost pipes/silicon hoses and Audi R8 coil packs/harder spark plugs. Haven't experienced any flat spots and it revs freely up to 4500. Never felt the need to go higher, in fact rarely go over 4000.
Superchips is probably the mildest remap, APR look good, but put off by people I know in the States, who have had problems, REVO seems a bit aggressive for my driving style.