Benchmark DAC 1 or Musical Fidelity Tri Vista?

Should I get a Benchmark DAC 1 or a Musical Fidelity Tri Vista? Front end is Onkyo Integra DPC 8.5 universal player, Rotel RC 995 preamp, Odyssey Mono Extreme amps (awesome, just awsome amps), Paradigm Studio 100 V 3 speakers with Rel Storm 3 sub-bass unit. Good cables throughout with Audioparts Mas Signature Reference bi-wire speaker cables and Audioparts Mas Signature Reference interconnects, and Signal Cable Speakon for the Rel. Clean power to front end with Powervar power conditioner.

May replace preamp and speakers but first would like to try a DAC to correct system's perceived mild to occasionally moderate harshness on the upper end. It sounds great but could be better. Dakiom feedback stabilizers throughout have helped greatly and I've done pretty careful testing with and without the stabilizers, but I still want it to sound smoother with no loss of detail.

So......which DAC should I buy? Thanks.

ps If I go with the Tri Vista, how often do the tubes go bad?
Still needing help:
What about the new MF 3 pack? Better, worse or same as TriVista DAC?
Or what about the notion of the Benchmark DAC 1 paired with the MF X10 buffer?
Well, despite receiving no recommendations in this thread, I was--somehow--able to decide on the Dodson 217 Mark II D, with the upgraded 218-like software (not an exact replica, but a "trickle-down" from that of the 218), and with an isolation tranformer upgrade coupled to one of the inputs. I absolutely love this unit (for specific reasons) and plan to mention (what I perceive to be) at least some of its outstanding attributes very prominently in my upcoming review of the magnificent Intuitive Design Summit loudspeakers.
Congrats on finding your digital bliss.

In your search, did you audition and form some opinions on the components in your original messages?

No dealers carried any DAC's other than Wadias, which started around 7000 dollars. So there was no opportunity to do so unless I wanted to buy and resell the above units, since most sellers don't want to send out a piece without a firm commitment to buy. I had seen the Dodson and saw a listing by Pardales, who answered my questions and stated that this was an excellent unit. Duane (my dealer) doesn't sell Dodson, but had heard several of them in friends' system and they had always "sounded good". So, I pulled the trigger, and hit the jackpot with this unit. Pardales had said, "You won't be disappointed." No kidding. What a great seller he was. This sounds kind of obscure, but one tipoff was the obvious care he had taken in packaging the unit with a double box.

So, everything was evaluated via word of mouth or emails, second hand, but nevertheless it worked out extremely well for me. Yes, there are some who argue in various threads, and there are some disputes on this site, but my impression is that the Audiogon crowd is a (mostly) outstanding group of people with discerning (albeit variable) taste in high end audio and impeccable integrity. Pardales is a stellar example, in my experience.
Thanks for sharing your experience.

In the ideal world, we should all have a shoot-out among some finalists before buying. In reality, this is often an intelligence gathering and analysis exercise and buying components unheard.
Why not also look at the RME ADI-2, Apogee Mini-Dac, or the Lavry DA10. All offers great sound quality for the price.

Thanks for the input. I don't doubt that the DAC's you mention are fine units. However, I am now "done", and am extremely pleased with the Dodson. No changes for the forseeable future in anything anywhere in my system. Others may want to consider auditioning those units, however.
"No changes for the forseeable future in anything anywhere in my system."

Yeah, you say this now but wait til next month! We know the disease around here well.
This Dodson is just a GREAT unit, and it's a vital link in the chain leading to the fabulous Intuitive Design Summit loudspeakers. Here's a link to a review of the Summits, in which there's a (not very good) picture of the Dodson, and in which I stress the importance of the Dodson's presence in the signal path:

Review of Intuitive Design Summit PSL 624, including references to the Dodson 217 Mark II D DAC with its ugraded, 218-like software