I have not worn one with a provider during the past two or three years, but both my wife and my former best friend-with-benefits/lover both liked when I wore it.  
The only important thing is the pressure has to be right, lower than the arterial pressure in your penis but a bit higher than the venous pressure.  You will know if you get and keep an erection without pain or bruising, it is the right pressure.

Ivanka Flowers out in LA. She applied it and it was great. The size is important so beware. But she was very good at applying it. I haven't used one since but it wasn't a bad experience...although drinking sake before didn't hurt.

I have thick ones, thin ones, big ones, small ones. But, I need them to maintain.
Just experiment. I have the different sizes and strengths because I like the feeling differently on different days.
Solved my ED problems really well.  
Just make sure not to cut off the blood supply for too long. You can break your dick. Lol.

I have found them to be a great sexy toy that most mature men have never tried before but once they do they see and feel the benefits

I bought a set of 3 basic black rings several months ago. They work. I use one a lot of times but don't always need to. The only downside to me is the constriction makes my ejactulation less forceful.

Not for everyone but open mindedness and trying something new is always exciting!