MAME is more for history and HBMAME is made for hacking fun. But it's not agard's fault that he has these feelings, it's MAME's. Like you said the argument for certain hacks being in and others out is flimsy as hell. No proof and guesses (i.e. seeing Phoenix version of a game in 1 arcade then saying they were all regularly used and now everyone updated to cleaner versions which aren't in MAME), higher preference to higher quality hacks (1 of trap's hacks found in 1 arcade and then everything he has touched goes in MAME), and then there are other hacks that have gone in arcades but were blocked from MAME because a mamedev labeled them "made for MAME". Certain multicarts blocked because 1 mamedev thinks it's crappy. Yeah I would say flimsy at best.