I currently prefer and use Roper grips from Altamont.
Mine are a round-to-square conversion. It's a pity S&W doesn't make more square butt grip frames, but I suppose square cannot so easily be converted to round.
I like the modest amount of material behind the trigger guard. So many grips fill that area in, pushing the fingers too low on the grip. The Altamont Ropers might be a bit too fat at the base but I like that they are very narrow at the top and have no palm swell or coke-bottle. I had to cut the Ropers to relieve them to insert and eject full moon-clips on the left side.
I don't like any grip that covers the backstrap (unless it's a Dan Wesson or Ruger that has none).
I don't like finger grooves. They never fit.
I don't like grips that fill in behind the trigger guard.
I don't like palm swells that are always too low.
I don't like aggressive textures. Checkering is fine. Smooth is fine.
These look perfect. I know Altamont makes similar "legacy" grips, but their selection is extremely limited at the moment.
The "Magna" style grips are a lot more popular. Many of the still affordable S&W's from the 1950's featured the rounded style Magna grips that Altamont reproduces as the "classic panel" style. Later, the grips were left cut square. Altamont reproduces these awful grips under the name "service panel."
I'm not sure if the Magna grips were intended to give some width to the top of the backstrap or if they were just intended to relieve the factory from fitting the grip panels to the semi-circle at the top of the grip frame, thus saving skilled labor and costs. Whatever it is, I'm not a fan of Magnas, at least not if I could have the earlier fitted style.
Here are some for the Colt from Eagle Grips.
Admittedly, these grip panels have poor proportions for barrels longer than 5". In that case, I suppose I would prefer the Roper.