19-1 caveats-
If you want to get Gradius or Ghost's n Goblins to continue, that might be a problem. I have owned 3 different variations on 19-1 and not one of them will do it. even if I make it the only game on the menu and use the coin-up feature.
if you are into defender/stargate, be sure to get a board with the 6 button support.
if you are really into mario bros. the emulation feels a bit clunky. not smooth like a real PCB but still fun.
if you are into joust/bubbles/robotron, be aware the emulation is old mame and the games play really fast. if that's why you desire a horizontal board, best to wait for JROK to run some new boards, or use the latest mame version.
if you are a high score afficianado, don't get your hopes up. the high scores won't save even though you'll see a dipswitch for it and advertised statements that they will save. once again I have owned 3 variations on a 19-1 and not one does it.
you are getting exactly what you pay for in a 19-1, old mame emulation. but for under 100 bucks it is a fun choice for the general enthusiast.
if you want a wider variety of games which play very smooth the ArcadeSD is hands down the best. that is if you want things like Moon Patrol, Berzerk, Frenzy, etc. and the option to have future games added to the board