I've never liked MAME. There's too many forks and variants of it, there's too many damn settings to configure, even then it very rarely works properly. What bothers me the most is MAME is a massive collection of little "emulator cores" for the hundreds of different CPU, sound chip and graphics chipset configuration found in arcade games. MAME even handles 3D games. How can a program like that maintain accuracy when emulators for just one console still struggle to attain perfection?
Not to mention software emulation, by nature, can never be completely accurate. When CPU X has to impersonate CPU Y along with sound chips and graphics chips, it takes a disproportionate amount of computing power to perform. Software emulation can never be perfect until modern systems become fast enough to emulate at the transistor level. Until then, everything today that is "100% playable" will always be an approximation. Considering ROM files are useless until the code they contain is executed by the correct machine, it should be a no-brainer that hardware should come first. Using original carts on a RetroN5 is no different from ROMs and emulators on a PC and is therefore pointless.