Snap Pro X is the best program I've ever seen. Ever.
Im sad to say I payed money for "Screen Movie Recorder"
That one makes you hit F8 to begin, slows down the computer dramatically, records it's movie -- then you must hit F8 or select stop from the menu bar. At that point the dock freezes, and the program stops responding.
It would sometimes output a movie file, but most of the time it was lost in the forcefull quit.
Snap Pro X is simple to use, records easily, and then makes a movie file. The dock doesn't freeze, and there is no huge memory problem. The .mov file is usually huge (GB in size), a quick run through Visual Hub and that is fixed.
One thing that was a problem at first, turned out to work even better for me than before. Snap Pro X uses the default Command+Shift+3 to open. This effectively stopped me from quickly capturing screen shots, as I would have to open it, select "full screen" then tell it to take a snapshot. (rather than just hitting command+shift+3)
There is a handy AppleScript in the application folder (for snap pro x) that takes an instant snapshot. Using this applescript with keyboad maestro, all I have to do is hit F16 now -- and I have a screen shot on my desktop.
I just have to say I'm very impressed with this program.