I've had my Gilmore Lite+DPS for a while and it is, to me, the best amp I've heard yet under $600. I haven't heard every desktop amp out there but I have owned or still own the Headroom Micro Amp, the Millet SSHT, the LD MKIII. I have spent time with the Matrix M Stage, LD MKII and Auditor. Portable amps can't compete.
I just want to note that the DPS does make a nice difference than without it. I originally purchased my GL from Justin with the stock wall wart and later picked up the DPS from another Head-Fi'er. I can't say it's a night and day change, but I will say it's a significant improvement. Well worth the price I paid. Not as sure it's worth Justin's price but I feel it elevates the amp's performance and is worth street prices. EDIT: 7/11/10 - I have been thinking of trying the Sigma-22 with the GL to see what that will do and compare it to the DPS.
The GL is the closest I've come to a wire with gain in this category. Even though there is no gain selection, it's an extremely versatile amp. I've had IEMs, portables, full sized, closed, open, planar, dynamic, high/low sensitivity, high/low impedance headphones, cheap, expensive. Grado, Senn, Beyer, HiFi Man, AT, Shure, Denon, AKG, SkullCandy, and others. A lot of headphones have been plugged into my little GL and it's handled them.
No noise with high sensitivity phones. No strain with power hungry phones. It does everything with a very low sound floor that makes it a nice black background. That and the ample power makes many headphones sound effortless when played at even above moderate sound levels.
The GL is a very balanced amp that doesn't seem to color the music that other amp's I've heard can do. The amp is nicely refined and very well controlled.
I'll reiterate what several others have already said about the pairing with the Senn HD650, it's a great mating. Although that Senn was never to my taste, I finally thought I reached it's full potential with the 650/GL.
I think the K-70x is spectacular with the GL. Talk about detailed! And I still enjoy the music. But, hey, I'm a detail freak.
The HE-5LE, which has been said to be a difficult headphone, works very well with the amp. Still the best headphone I've owned. I do have to listen to it with the dial at about 12:00-12:30 for moderate levels. Although it does start to lose some of it's composure at very high listening levels past 3:30 on the volume knob.
The T1, on the other hand, is (one of) the best headphone(s) I've heard. I've had the good fortune (or a curse?
) to spend some time with the T1 and my Gilmore Lite. This is a spectacular headphone/amp combination. I listened to the T1 through two other amps for comparison. I think the GL was my favorite. What, I felt, a neutral paring!
The Denon D7000 was not my favorite headphone as it's too bass heavy for me. The GL did seem to tame and control the bass somewhat. Just not enough for me to like the headphone overall.
I had the Grado HF-2 for a while with this amp and although I felt the two worked well together, I didn't feel that they worked that much better than with the Headroom Micro I had. But I've felt that Grados are a bit more forgiving of amps than other headphones.
EDIT: 7/11/10 - I received the HD800 on the 9th and have spent the better part of two days listening to them. While I haven't had the opportunity yet to compare it to the T1 I can say the GL, again, works effortlessly with yet another headphone with this Senn. The GL really allows to HD800 to show off. More than just a few at the NJ meet really enjoyed the GL/HD800 pairing.
EDIT: 7/26/10 - The GL can't drive the HE-6
EDIT: 7/26/10 - I have now have the trio of the 840/M50/D1001 in my stable and each one of them sounds great with the GL. The thing it does best with the three is help control the bass better. This is especially important with the M50.
EDIT: 7/26/10 - I've had the opportunity to listen to the Asgard and don't feel the amp is close enough to the GL that I would pick one up.
So those are my musings on the GL. Is it the best amp ever? Probably not. Are there better amps? I'm sure there are at higher prices. Will I ever want to step up? Maybe. Who knows? The GL is serving me well right now.
Peace