Sound wise, the Trivista is my preference by a long shot, of the three. The other two are very fine amps and it should not be concidered that I'm 'dissin them in any way shape or form, but for me the Trivista has proven to be the ticket.
Looks wise (WAF) the Rowland or the Moon are MUCH more attractive. Although the looks of the Trivista grow on you and the blue feet are super cool at night.
Robbyg is on the same wave length as I am, POWER is the key to this speaker and the Trivista delivers POWER is spades. It's also VERY warm sounding to me. I have not grown tired of it and I've had it for well over a year now. I usually find it takes that long for the faults to come out. To my ear it is very smooth and the sound stage is wide, bass extention is superb and the mid's (what Dyn's excel at) are just a thing to behold. I like female volcals, blues, world music and good 'ole rock'n roll. I listen to classical but usually only as background music. I'm not a big fan of loud either, I don't think I have ever turned up the Trivista past 11 o'clock on the volume knob. I like a well defined amp/speaker set up at low to mid range volumes. This being the case every time I go to a stereo store to demo something I end up asking the salesperson to "turn it down please". The C-5s will sing in my humble opinion with the power of a Trivista 300 at low to mid volumes. They will shake the house if you turn it up.
Hope this helps.