I was thinking of giving light guns another shot for Mame, since I could never get the act-labs one working right for some reason.  Ultimarc has come out with what looks like a pretty cool solution though-has anyone tried it?  

I've got a pair of them mounted in Namco's guncon 2's. They're great, but I haven't had a chance to fully test them.  The limited testing I did do showed me I'll be able to sell my other guns (the LCD Topgun's) which were fine, but you had to really be too far from the cab. With the aimtrak's, the distance is cut in half and they work on all monitors.

edit: forgot to add that Andy (Ultimarc, the creator of the aimtrak's) should have these boards available in their own gun shells soon.

Good to know-I saw that he might be selling shells with the guns sometime soon, but I thought there might be some shipping issues from the UK with anything gun-like.  I was half thinking of just keeping an eye out for some busted arcade guns and mounting inside of them, but we'll see what comes up.  The problem I had with the act-labs gun was that it never seemed to work on all games the same way, and I'm guessing it had something to do with screen resolution changing.  I could also never get offscreen reload to work in area 51.  I've only spent maybe a few hours with it trying to get it up and running, but I'm not sure if the problem is with the hardware or the software.  This sounds like a more reliable system anyway, and I really like the ultrastik that I bought from ultimarc a couple years back.  

On the issue of game to game compatibility, you may not be aware but some of the games, you must first calibrate the gun in-game, I think via pressing F2 when it boots up.  This is a normal procedure to follow from the real hardware arcade machine, not a flaw, so your other gun may work ok with those games.

I've tried the in game calibration for some games (where I could find it), but still no luck.  I think I have area 51 aiming correctly, but it runs really slowly, and I can't get the offscreen reload to work at all.  Point blank is just completely uncalibrated, and I can't seem to get it into a service mode where I can calibrate it.  Sounds like it'll take a little more digging.  First problem is probably going to be a better CPU in the cabinet though-the old a** p4 I have in there doesn't seem to cut it for games with a CHD.

I bought the kit and have a spare gun lying around to put it in but I just haven't gotten around to installing it, I will one day tho.  

Quoted from The Loafer

edit: forgot to add that Andy (Ultimarc, the creator of the aimtrak's) should have these boards available in their own gun shells soon.

Good to know...I'll hold out for these outta laziness but I'm totally ready to add some guns and just needed something like this to come along.