I'm wondering why Retropie doesn't come with these other, more compatible cores as their default (instead of Mame). Seems based on what you folks are saying, it's a better option.
it does? lr-fbneo is in the default image and is recommended in the docs
lr-mame2003-plus is an optional install, which makes sense to me as it has an ever-changing romset, so you'd need to manually build it (the ones in circulation appear years out of date). i don't think that's a reasonable expectation for users to do by default.
the same could be said of lr-fbneo, but it appears pretty trivial to acquire near-current sets.