I'm yet another user of MagicQ PC for the majority of my lighting work. As others have mentioned, it's a very powerful platform that can be implemented for under $100 assuming you already have a laptop to run it on. I have to admit though that when it comes to light consoles, I really like the ability to actually push buttons and move faders. The PC solution is great (and I have mine running on a tablet PC), but once your setup gets beyond a certain size and complexity, having a wing is a must. Unfortunately, the wings are extremely expensive and even the MagicQ MIDI interface will cost close to $1000, at which point I ask the same question - if I'm going to dump a lot of money into a lighting solution, should I just get actual hardware console instead of one that requires a PC?
To help bridge the gap I also use a Behringer Eurolight to control my PARs and effects. I personally find it difficult to design with conventional stagelights on a purely PC console (even if it's on a tablet), so the Eurolight fills that void while I leave MagicQ to handle my movers. I've been using the MagicQ / Eurolight combo for nearly 10 years now and it fits my needs well enough, but I would certainly prefer to have all that control on one console. Of course that's going to cost serious money though (hence I have yet to do that).
Hope this helps!