It depends what you are looking for. I ran Gefell > PSP-2 > MiniMe > 671 for a very short time and while the results were the best that I have ever achieved, I did not want to lug all that gear around all the time. I switched to PSP-2 > D50 and have not looked back. So much easier in terms of battery life, weight, and portability, and still sounds great. The PSP-2 > MiniMe sounded fantastic; very clear and great presence. The PSP-2 > D50 is darker and more colored, but also sounds great.
Basically, I live overseas in developing countries. I travel a lot and wanted something very portable. PSP-2 > D50 is so convenient that any sonic advantages of the larger rig were outweighed by the portability factor. I can change levels on the D50 and don't have to mess with a tiny screwdriver to change the levels on the MiniMe. I don't have to worry about DVD batteries exploding or short circuiting when I plug them into the highly unstable electrical systems around here. I can go into virtually any well-appointed regional market and get all the AA batteries that I want to run the thing. Sometimes, enjoying the situation without the hassle is better than having the nth degree of resolution possible. PSP-2 > D50 gives me 90% of what the PSP-2 > MiniMe gave me for a lot less headache. That is worth it to me.