I'm having an intermittent issue as well. The car will get cold but only after a really long time (30 minutes or so).
I hooked up my freon meter to it and noticed something odd. The meter was going from the blue area (good) into the green area (bad) and back. Corresponding to that fluctuation I could hear an audible clicking that I traced to a pulley (for lack of the right word) that was engaging and then disengaging. When it engaged, the freon level would decrease, when it disengaged the level would increase.
Here'* the "pulley" I'm talking about.
I also took a small video (small in length, large in size about 5 MB). Click this link:
Is that my compressor? Is this indicative of a leak or something else? Any help is of course appreciated.