Well, you would have to test each 'cooler in the specific application (or one application for all tests) to achieve a satisfactory comparison.
Basically if a 'cooler is over 80% efficient and has less than a 8% pressure drop accross it, then its a good one for the application (discounting charge volume - i.e. as long as its not too big).
Testing for temp is simple. Insert a k-type thermocouple before and after the IC and record the temp drop.
Testing for pressure needs a boost guage connected before and after the IC. Without making an adapter that fits in the IC hoses with a fitting for a pressure reading, the compressor output and any manifold pressure connection (LDA?) can be used, but his will also record pressure drop in the intake piping.