I've auditioned both players in my system, and bought neither; however, if my choice were between these two and my focus was 99.99% Redbook, I would get the ARC. The TriVista is an excellent SACD player and a very, very good Redbook player. The ARC is an excellent Redbook player.
The TriVista occasionally sounded a bit congested with massed strings on CD, and was a touch muddy-sounding in the bass (again, CD). The ARC was none of these things, and its strong, taut bass was its strongest point.
I don't think SE vs. balanced would be a huge issue; really all you're missing is some gain. If you had the choice with the player you decided to get, continuing to go all balanced would be better, but shouldn't be the deciding factor.
The TriVista occasionally sounded a bit congested with massed strings on CD, and was a touch muddy-sounding in the bass (again, CD). The ARC was none of these things, and its strong, taut bass was its strongest point.
I don't think SE vs. balanced would be a huge issue; really all you're missing is some gain. If you had the choice with the player you decided to get, continuing to go all balanced would be better, but shouldn't be the deciding factor.