So, I just recently got into this and have been on quite the shopping spree. My experiences to date:

I started with a few different steel cages from lockthecock.com. The devices were all fairly similar. What I liked was they came with three different ring sizes and were super easy to put on. The cage just slid down on the ring, snapped a padlock and done. The con, they were huge. Like way to big to wear under clothes imo

I then found a much smaller cage from Terrence. The pros were it was very constraining, pretty discreet and really prevented any arousal. It was purely maddening to have on (in a good way). The cons were it was virtually impossible to put on. The lock was embedded in the mechanism (no separate padlock). Basically you had to sled the lock on thru which was impossible unless perfectly aligned. I got so annoyed with it, that I threw it out

I then ordered The Vice from Locked in Lust. This was my first non metal one. It just came today, so I don’t have much experience with it but so far it’s my favorite. Super easy to put on, light weight, comfortable. Only con to me so far is it’s not steel and I really love the steel cages.

I have one more coming, not sure the name. It’s coming from China, so I’m guessing it’s gonna be a while. I will definitely order a Holy Trainer based on your recommendation next though

My general learning from all this. 1) size of the cage is critical. Obvious I know, but I could have saved some money if I knew this up front! 2) Complex locking mechanisms can be problematic. It’s hard to beat the good ole padlock. 3) comfort and ease of putting on is super important. I wish I had paid more attention to the online reviews

It has been super fun for me though. I’ve really enjoyed playing with them on and can’t wait to do more. Wearing one long term isn’t an option for me, but wish I had incorporated them into my sessions years ago!!!