I love bothe gauges, but there are some subtle difference that might make one more appealing than the the other.
I know you can display up to 8 gauges at a time on the interceptor, but Im sure it so small you can't read it, while a scangauge 2 displays 4 and is easy to read.
Also from what I have read egt, map, afr, fuel pressure and a coule of other good to knogauges don't come built in to the interceptor, but they do come on the scan gauge 2.
Both are great and probably even though I do not need to I will probably find room for both in my car.