I had 1A03 with Barto this fall. He was alright. At first, his Czech accent is difficult to understand, but you get used to it. Make sure you come to his class and listen to his general statement on what to do and try to beat him to it (in terms of time) while he does the examples on the board. The only problem I had with him is how they have different terms for some concepts in Czech Republic, so make sure you do some of the readings, at the very least. It's a small problem, however.
On the plus side, he's pretty entertaining and humourous, and is clear after having him teach for a week, because by then you're probably used to him. He's pretty open to questions, but he didn't get that much during the semester, so I'm not too sure, and he's open to giving marks for mark errors on your tests.
Here's his website:
http://www.karlin.mff.cuni.c z/~barto/