I love MAME, but must admit I get tired of trying to keep it up-to-date.
Every version gets more accurate, but slower. They also go and do things like completely change the picture formats meaning you have to replace all the art files. The huge CHDs that run like crap are also a pain.
With my retrobox only having a 1.66Ghz XP processor and 512MB RAM, the more recent 3D games (without hardware acceleration) that get added don't really interest me. If I want to play a 3D game, I'll use a console EMU or modern hardware with 3D acceleration. Now and then a reason will popup good enough to force an upgrade, but not often.
I think I've got a complete set of 0.106 on DVD's, then progressively updated to 0.114 before getting board. Once all the last of the great 2D fighter games were added my MAME experience seems very nearly complete for nostalgia purposes.
The only recent addition that stood out was Street Fighter III, but it runs 100% better using nebula: http://nebula.emulatronia.com/
...and that's the thing - many CHD and modern games run better in the stand alone emulators vs MAME.
Great project though. In fact, I think I'll nip off for a quick game of Cadillacs and Dinosaurs right now...