Soliloquy voices their speakers partly with Sim Audio amps, and that never hurts. That said, the 5.3s do respond to tubes quite well so it might come down to personal preference. I've heard Sim and Rogue stuff, but not together and not on the 5.3s, but I'm pretty confident you'll get more extended highs and much tighter bass with the Sim, although you'll undoubtedly give up some of that tube warmth which I have heard with the Rogue. I've had my 5.3s for over 2 years, and personally I'd go with the Sim because it will better allow the 5.3s to portray the level of detail they're capable of while not letting the bass overwhelm the presentation. Your call, but as always, try before you buy. Best of luck.
Tim
Tim