There are several recent threads about compressors. It may be more useful to post your question in one of the existing threads. I have the 30 gal single stage oil-less 6hp/1.5hp Craftsman that I use for portability and a 60 gal 2 stage IR for my "fixed" location, so I can't speak specifically to the model you're referring too, but I can say you should get the one with the highest cfm at the highest pressure you can afford.
A big tank is only really useful when your compressor can't keep up with the job you're doing. The greater the capacity of your pump, the smaller the tank you can live with.
LWW