Having been a fan of the R-type series since the late 80's, I always thought that Leo was quite a different game from the regular series. But it's still an R-type! Since I already own R-type and R-type II on original hardware, I wanted to have Leo to join the set! Unfortunately an original board is really expensive. But converting a Major Title 2 to R-type Leo is much cheaper and really easy.
I picked up a MT2 for $225, EPROMS cost me $20, and of course there's a bit of time to convert.
I ended up following the instructions made on the Arcade-Projects forum, my most favorite place to converse with fellow arcade enthusiasts: https://www.arcade-projects.com/threads/irem-m92-conversion-log-major-title-2-r-type-leo.4680/