These are expensive blocks, but they're a lot of fun. I got my son the set of 8 that comes in a little grey case for when we go out to eat and travel and he loves them. If they weren't so pricy, I'd replace all of our wood blocks with them.
As for choking, these are similar in size to wooden blocks we have from Ikea, Haba and Melissa and Doug. I would think that maybe the wheels are the choking hazard, not the blocks themselves. And really, you dont need the wheels to have a good time with these if your toddler is playing with them.