The epoxy coating is not “rubbery”- it is very hard and durable.
I had to go with the 48″ tall x-pen- and I wish it was shorter but Griffin, my English Lop was clearing 3 NIC grids high which is about 3 1/2 feet. Griffin is a larger rabbit- and he is younger, approx 9 months old now. But when he stretches up to beg for a treat he is probably close to twice the height of Schroeder (the Mini Lop housed next to him). I miss being able to lean over and grab bowls, etc.
So it really depends on the rabbit- Griffin was always getting into everything and clearing anything we used to block the stairs until we got up to 4 feet tall. But most larger rabbits are supposed to be mellow- and he is getting more mellow and cuddly over the past couple of months.
Just to make sure he does not try to climb or jump the 4 ft pen I have a piece of Coroplast on top- I was afraid it would make the pen dark (block light) but it really does not since the pen is so tall. And ever since he thinks there is a “roof” to his cage I have not seen him try to jump or climb it.