As long as you work up to it, you can do pretty much anything in them. I'd avoid lateral work, where it is pretty easy to sprain an ankle with the free, due to the elevated heel and lack of support. However, you can get frees with a strap across them which are meant to be ok.
I've had a pair of free trails for 18+ months, and they're still going. Heard that the standard ones are less durable though.