I've had a Soekris dac1541 since late summer last year (~9 months or so). It's really good. I made a volume-matching AB (not ABX) switching box, and I could not hear much difference between the 1541 and a Gumby. Sold the Gumby, it's not worth the desk space and it has fewer features (not to mention it has that obnoxious relay that snaps loudly at night in a quiet house when it has no USB signal lock). The original filters are pretty neat and have audible differences — admittedly with sighted testing, but that's way more than I can say for any other filter-switchable DAC I tried.
I also recently picked up an RME ADI-2 DAC to play with its DSP. Very neat device. The built-in parametric equalizer works well. I've never heard a 007A+Carbon combo thump this hard after I EQed it to (as best I can without a measurement rig) match the Harman curve (based on Tyll's old measurements of the 007). On the downside, I think it increases listening fatigue somewhat, so it's probably not ideal for long listening sessions. For short periods (like 30min or so), it sounds pretty fantastic and impressive. With all DSP turned off, I cannot hear meaningful differences between the ADI-2 and the dac1541, but I must admit I didn't try very hard.