These are my pros and cons for each, YMMV:
Rivera
Pros - ease of use, is an attenuator
Cons - can only use tube amps with it, not rack mountable
Torpedo Studio
Pros - lots of IR options and controls/features to tailor sound; can use preamps with it, PC editing, rack mountable
Cons - not an attenuator, expensive
Overall, I think the Studio is "better", but that's only because you have way more options/controls. It's also over 2x the price of the Rivera, so it's not a totally fair comparison when you look at them side by side. But, as far as I'm concerned each of them do a good job for what their designed for.
P.S. I forgot this one is with the Rivera, too: