You know, I loved my Dreamcast back in the day. But I went back to play it and it really didn't age very well. I think it has something to do with seeming like it is trying to do a modern game but looking and playing so primitive by current standards. I think I enjoy retro more when there is a marked difference, it just feels like they are trying to do more and failing (even though that isn't really the case). Recent Soul Calibur games spoil the first one, despite it being one of my favorites - with even part 2 blowing it away. Gauntlet Legacy seemed just plain bad, and I used to love it. Sonic Adventure is a terrible game that can't lean on graphics like it once did. Crazy Taxi was still mindless fun.
The problem was even worse when I plugged up the Saturn. 2D games were fine (XMen vs. SF, Guardian Heroes, MvC 2, etc.), but anything it tried to do in 3D was just cringe worthy. Panzer Dragoon was still kinda fun, but man that framerate was terrible.
If I had to choose, my favorite console is the SNES. There are a ton of games that I still love to play all the time. My WiiU menu looks like an SNES "Greatest Hits" board with all the virtual console versions I have. Cybernator and Contra 3 are still a couple of my favorite all time games.