Every thing so far is spot on. I do own a sp101 chambered for .32 H&R, and I own an undercover and bulldog from the Stratford CT era. The charter arms professional will have a better trigger, lighter weight, and one more round. I've always been leery of the thin cylinder bolt on the charter arms revolvers, but it has worked OK on mine for 20 years. I don't like the looks of the "backpacker" grips on the charter arms professional. I would replace the grips with a set of classic bulldog grips, but that's just a personal issue.
The sp101 has a heavy trigger and there's not much you can do about it. Wolff makes a spring kit with a 8 pound trigger return spring (factory is 10) and 9, 10, and 12 pound hammer springs (factory on centerfires is 14). I've replaced the hammer spring with a 12 pound and have had no light strikes, but I suspect you might have a problem with the lighter weight hammer springs. There are some other things you can do to smooth up the ruger trigger and there are several videos covering that on youtube. But still, these will be marginal improvements. The ruger factory grips were too small for me. However there is a grip maker (out of thailand I believe) who makes hardwood sp101 grips in various styles. You can order directly from them on their website, or order the grips through amazon. Just go to amazon and search for the vendor: "handicraftgrips".
I like the .32 H&R. It serves me as a sort of reloadable .22lr. For the trail, a 115 grain cast at 850 ft/sec is dandy and for more serious work, there are published loads which will allow you to drive jacketed bullets to 1,100 ft/sec. There is also factory loaded "boutique" ammo which will achieve the same velocities.
As for which to choose, I would opt for the ruger, simply because I feel that it is more robust and with the .327 federal, possibly more versatile. The best answer, though, is to buy both. Lately I've been avoiding gun shops, fearing that I would find a charter arms .32 H&R nitride professional in the display case, and it would be impossible for me to pass it up.