For your style let me throw something out there.
Have you ever played one of the DrZ amps? They are low wattage class A, and some of the combos used can be bought for 600-750. If you havent checked them out, they're worth considering, especially for country/rock. I don't own one myself, but it's likely my next amp purchase. I have played several and they are all very good.
As for thr Rivera, they remind me of a Twin sort of. Pretty close to a late 70s Twin Reverb for me, slightly different feel. If you need all the clean headroom it will probably to well for you. Frankly I'm not a big fan of them, but YMMV.
H2H