I have a 3DC. for my cornet. It's nice, but I like my Benge 3 better.
I have a 3TC. for my Olds Special trumpet. It's a little deeper and more V-shaped than a Bach 3C, enabling me to approximate the timbre and playing characteristics of my Olds Studio trumpet.
I bought a 3M., but it didn't play as well as my Bach 3C for me, so I returned it.
One minor thing about them that I don't like is the shape. It's all taper with nothing much to hold onto when handling them, making doing so slightly awkward.