I have a 329NG, and I highly recommend the Pachmayr grips that come stock on the NG series! They are very compact, and have a nice thick layer of rubber over the backstrap. Downside is that all that rubber increases the length of reach to the trigger, which might be an issue for those with a short trigger finger.

Clearly, S&W has never really caught on in any big way to how much sense it makes to cover the backstrap with some recoil absorbing rubber. Over at Ruger, after a while they figured this out, and all the current DA revolvers have covered backstraps and everything except the SP now comes from the factory with Hogue Tamers, save for the old school Redhawk.