I’ve got a wee ride (front mount seat). The front clamp struggles to fit around the head tube on my MTB, you do have to ride a bit bow legged to avoid bashing your knees, and you can’t get off the front of the seat when you stop.
On the other hand, it’s great to have the kids in front of you so that you can talk to them easily, and they can see better. I took both of our little ones round the blue at Whinlatter a little while ago, and they absolutely loved it. Great to have them right in front of you so you can make sure they really are enjoying it and they can see the bumps coming up.
For fun rides I’d definitely look at front mount. For transport, I’d probably look at a rear seat.