Pro Control is a very high quality EXPANDABLE control surface. You can add more faders to it, as well as a custom protools keyboard and dual motorized joysticks. It has absolutely superb faders and nice scribble strips, where you can clearly see the name of each track by the associated fader.
The Control24 is still a high quality control surface, although the fader beds are still really great, they aren't as nice as the pro control. It doesn't have some of the bells and whistles of pro control, and is NOT expandable. It does offer more faders than the pro control, as well as 16 nice preamps and a submixer.
Which one is best for you really depends on what your longterm needs are. As for learning pro tools, you can learn it without any control surface at all. The control surfaces essiantially just make for a more effiecient workspace.... i personally like the control surfaces, although I've been quite happy with a mouse