I demo'd the Trivista 21 for three days several months ago and it sounded very good. The soundstaging was excellent with just a touch of warmth. Good detail, good bass and reasonably good treble extension. Not as clear, dynamic or holographic as a dcs Elgar/Purcell rig but, eminently enjoyable non-the-less. I would call the soundstaging it's strongest point even though overall, judging by the boundries, it was just a tad small in my opinion - though probably close to being true to the live event. I tend to prefer just a touch of bloat in my soundstage. To me this produces a "livelier" and more "immediate" sound. Be careful with these comments though, as system synergy also dictate the extent that this characteristic is displayed.
I have also owned the Benchmark. It is clear, dynamic and extended. Soundstaging is good but, not as good as the Trivista. To my ears, the solid state signature was always present in the form of a slightly "bleached" sonic character as well as a slightly "flattened" stage. It was almost too squeaky clean to the point of exhibiting a hint of glare in the mid and upper registers. But, it is still a very good dac and it's preference over the Trivista or, any other dac for that matter is likely to be subjective. In other words, it wasn't my cup of tea but, it may be yours.
If you are considering the purchase of a "used" Ttrivista, be advised that Walter of Underwood Hi-Fi was selling brand new units for $1495 a couple months ago. This is part of the discontinued sale - no more Trivista's are being made.