I’m getting one! Hopefully installing in April. They are so helpful. They were running a promo so ours (but we have a teeny garden) is costing just over 1k. They are installing for us though which is a big chunk. If you’re handy I’m sure you can do it more cost effectively. BUT send them a photo and rough measurements and they’ll give you a cost really quickly
When I looked into it, I read some reviews that said other cats could get in and got stuck with no way to then get out - less of a chance of that with the other types of cat proofing options. And they really don't look like prisons, I've seen lots of photos of different gardens and most of the time it really blends in well.
I had it in my previous house and did not hesitate installing it in the new one. It is expensive but worth it for the peace of mind. Send them pictures of your garden and they will do you a quote. Ours was £3000 with installation. If you are handy and install it yourself, you'll save a load of money.