The standard MAME build is a command-line application. "Plus" builds were unofficial modifications created by various developers (most notably the Plus! team ) that added a graphical user interface (GUI) directly into the emulator. More importantly, they often optimized drivers and, crucially, improved support for specific arcade hardware, most notably the .
This is the #1 mistake new users make.
Because it is a "fixed" romset, you don't have to worry about your games breaking when you update your emulator software, unlike "Current" MAME versions. Managing Your Romset mame 078 plus romset