I originally found multiplicity after using synergy - however synergy doesn't work well with WOW's mouselook mechanism since synergy doesn't pick up "set mouse position" calls that originate elsewhere, multiplicity did, and because of this and my desire to use it a lot with WOW, i've percevered with Multiplicity Pro a lot longer than I should have. Key annoyances are
1) keyboard based screen switching. Can only use a modifier key and a function key. so i used ctrl+f7 and f8. When I press these keys, they still get sent through to the main machine's applications. So I have firefox open, I press CTRL+F7 to switch to my left machine, which it does, meanwhile firefox tells me about F7 starting 'Caret Browsing' mode.
2) Stuck keys. Had this in a couple of applications, ctrl/alt/whatever get stuck down on screen change. Most noticably, again using ctrl/f7/f8 to change screens, if i'm playing Sins of a Solar Empire (another stardock/impulse product...) the Control key gets permenantly stuck down in Sins. So you end up having to press control again to release it all the time.
3) Mouse speed resets. When I move from the main to secondary and back, sometimes the mouse speed is reset to the default setting. Since I like it a lot higher this is very annoying, so much so I keep the mouse control panel open in the background to reset it regularly.
4) The one that is whined about almost constantly. Just doesn't connect to the slaves at all. Troubleshoot the connection on the main "yes everything is working" telnet to the slave, yup that works, troubleshoot on the slave "everything is fine". OK so why dont you work? no logs, no reason, no clue. Sometimes an installation of Multiplicity Pro from impulse doesn't even end up with a service in the services application. That fixed the problem a couple of times before.
Having had a hard drive error a few days ago and had to reinstall vista x64 (disk defect in the 32 bit subsystem DLLs, rather killed the install ) I just couldn't get it to work, I spent 5 hours reinstalling it through impulse, no go, no service, no connection. Fixed the service with a batch file I found, still no go, everythign gives green lights but it DOESNT WORK. In fact today I even managed to get a new problem! When I press the 'switch display' hotkeys (it says its not connected) the entire application crashes out.
4-5 hours of reinstalling stuff later (oddly the 'demo' download of multiplicity /works/ but not the impulse installation of multiplicity pro), coupled with the stuck keys and mouse speed sensitivity bugs, I tried synergy again. Still no good with the wow mouselook problem there, so I looked around for other solutions and found Kavoom. Works with wow mouse look, i can set the screen shift keys not to have to be some hideous combination of F-keys that gets passed through to the application, it actually WORKS and connect, and it doesn't reset my mouse speed repeatedly.
Having tried with varying success on and off to use Multiplicity over the past few months, I've finally completely deinstalled it, and that is without doubt the best thing I've ever done with this application, i am SO glad to be rid of it and the sheer hastle of trying to get it to work. I do that for a job, I don't want to have to come home and spend days trying to do the same for such a simple application that gives no useful debugging input whatsoever.
PS - once you /get it working/ aside from the sensitivity reset/stuck keys issue, it generally works fine, its just reinstalling it that is a major major major pain in the ass, the sensitivity/keys issues are ongoing inconveniences you can 'learn to deal with', but having found something that gave me zero headaches and no inconveniences, i'm rather glad this final spate of issues with this product drove me away to find something better.
Honestly, multiplicity pro is the single worst piece of software i've downloaded/bought and tried to use at home in ... well ever actually. Its terrible, if you're thinking of buying it, seriously save yourself the hastle and dont do it! The demo might run fine but the product from impulse right now doesn't behave the same way at all.
It'll probably get fixed one day, but then again thats what i thought about the mouse sensitivity issue, the stuck keys, and the limited selection of hotkeys to switch displays, and that never happened either.
And no I didn't report it to support, I'm sorry but i'm not wasting my time spending days and days on that (this product hardly has good reviews around the net, and the support gets similarly bad reviews, and anyway i'm not here to beta test your software, the fact so many people report so many issues with the product means someone should be able to do some serious testing and fix it, if you need somewhere to start, get a clean install of vista, and install multiplicity from Impulse, no service registered. that shouldn't happen at all.)
End of rant. Really glad to see the back of this rubbish.
Good luck to the rest of you struggling with this product, and for the few it works flawlessly for, congratulations for you, hope you never upgrade your machine or have to reinstall it, because i've had to reinstall my os about 4-5 times during the time i've owned this product and its always been a pain.