Hi Islandflyfisher,
What you are asking for if anyone compared their TRL SA14 with one of the DAC listed may be rare indeed. Your best bet is to re-read the thread again. There is no doubt in several minds on this thread that the $550 cost will transform your player to a very high level. I have heard the Benchmark but in a foreign system. I did hear an a-b comparison with and without, and I barely heard the improvement.
There are just too many who have experienced the change in their system compared to what they had before and if you are thinking that this is a high risk decision, don't worry its not since the mod has a full refund.
As for the TRL SA-14 comparison to the Denon 3910 mod player, its more a matter of money in your case. Unless its important to you that you have the 'best' modded player. You might want to check with APL or RAM since TRL does not mod the 3910 which is ultimately the only way you will know for sure.
Good luck