The SP01 is better if you have big hands.
I have a new satin '75 that I love, and got it just the way I wanted--with trigger job, competition hammer, etc., only to find that the downward tang is uncomfortable to shoot. I really like the classic looks of the 75B without the rail and all, but I am going to have to sell it and buy the SP01, with its upswept beavertail tang.
I try to stay away from tacticool rails and all, but the extra weight of the rail isn't a bad thing. In fact, with the added front weight, beavertail, and palmswell grips, the SP01 is the most comfortable pistol I have ever shot. Now I just need to find one...