I have both - the playfield layouts are almost identical. MB is probably my favorite theme ever. Both play fast. Code is WAAAAAAY deeper on Elvira. It's not even close. Lyman coded both... obviously you can't lose either way. Elvira is far ahead in terms of code, and is only halfway done.
I am still shocked at how few mods there are for MB. Has always been a disappointment
But if you are definitely looking for a NIB game, get Elvira. There are tons of used MB out there you can find