I've said a billion times before, if you stuck with the same average PC spec with each update (for example a 2.4Ghz P4 with competent on-board graphics and sound), with the exception of polygon-based games, everything else took several steps back in terms of performance, due to the core re-write which was optimised for performance graphics and sound cards - something the MAMEdevs said they would never do as they believe in 'baseline emulation' without specific engines (hardware) to handle certain aspects like graphics.
They eventually did at 0.106, compromising performance on otherwise good PC's, meaning to get the same performance afterwards you had to seriously up the spec of your PC hardware (and hence, cost) to get the same performance results. Budget builds for bar-tops and small projects therefore got more costly, unless you stick to a pre-0.106 build of MAME.