From someone in your position of using them as an actual learning tool, not as review: I'm well into the first volume right now (though I've read a little here and there from the 2nd and 3rd)— the Feynman lectures being my first non pop-science book on physics, I think that, depending on the kind of learner you are, they can either be great or terrible as a learning tool.
If you're a person who learns in a linear fashion, get a textbook first.
If you're like me and you need the "big picture" and philosophy first before getting into the details, then Feynman is your man. The way I use them is I read a chapter, get the idea, and then look at a textbook or a website with problems and more detailed examples... that way once you go into the more complicated stuff, you already have an idea of what it's all supposed to feel like (intuition as someone said).
After all, the key word is lecture; Feynman makes a point of it in the prologue— they were lectures, and after the lectures his students went on to group studies and such. Feynman states the laws and principles and philosophy behind the science, and leaves it to you to use it as you please on your own.
He also does a great job in making his explanations colorful and entertaining (when possible, of course... I mean, there's no real way to "jazz up" probability distribution).