Anyone use these? How do they feel in the hand?

That's an antique. I had a pair (many) years ago. I have Herrett's Jordan Troopers (reshaped to greater and lesser degrees) on all my revolvers. The Pachmayr version, if I remember right, was a hollow plastic poor copy. The Jordan Troopers work well for those of us with long hands/fingers.

That's my favorite grip shape, although they are cheap and hard to keep from breaking. I used them until I could get some good wood grips similar in shape. Try wraping them in electrical tape to give them a little stability and strength. You can hardly find cloth electrical tape any more but that works best.

The shape is what I liked about them. If I get them than I'll have to look at filling in the hollow with something. Maybe super glue, and let it cure to strengthen them.

They were noted for being somewhat fragile. Pour them full of epoxy.