I can confirm that Mame 1.9 is fantastic on fw 1.4 - plays games full speed - including NeoGeo (overclock to 233Mhz) - including Neo Turf Masters! (love it!).
For me there's no difference beside the LCD-tweak options. For NeoGeo games I recommend GnGeo2x since it's more optimized and plays nearly everything in fullspeed with sound @ 266mhz... It's just great!