For what it's worth, I think you'll enjoy your new 642 ...
I own a short-barreled SP-101 DAO ... and older 649 Bodyguard ... and a 642-1.
I bought the 642 after sitting on the fence, undecided, for several years ... The SP-101 & 649 were both too heavy for me to consider them as real pocket guns, unless I was wearing a padded vest in cooler weather, and then they just pulled down on one side unless I balanced the vest with something of similar weight in the off-side pocket. The Ruger was obviously worse ...
I wanted something lighter, but didn't want to be limited to jacketed ammunition in the Ti or the later Sc/Ti guns ...
I ended up going with the 642, and it's the best decision I've made for a very lightweight off duty weapon in years. It fits in either pants or jacket pocket, and carries like it's not there. In my denim or leather jackets, I simply forget it's there when riding my motorcycle. In many types of slacks it simply disappears in the front pocket, especially if you're using a decent pocket holster.
All but one of the instructors on our staff now owns one model or another, and it's become the most common off duty weapon among most of us, because of its lightweight and ease of carry under the widest range of circumstances. A growing number of the better shooters in our agency have been adopting one or another of the latest lightweight 5-shot revolvers. One of my friends who used to carry either a 3913 or a Kahr K-40 off duty, now carries a new 442 off duty almost exclusively. He's a fairly active IDPA participant, so he spends a reasonable amount of time practicing, and he started spending a lot more time practicing with his new 442. He was pretty surprised by how accurately he could shoot his new little gun.
Now ... J-frame revolvers, and especially lightweight J-frame revolvers, DO take extra practice and training in order for most folks to shoot them accurately. I started spending a lot of range time with my 642, shooting both standard & +P ammunition ... and took advantage of having a 442 & 640 in our training vault by spending a lot of time shooting them when I wasn't shooting my 642. The 640, which was an early one rated for +P+ .38, allowed me to use a lot of some 110gr +P+ ammunition we were using up for training. That made shooting +P feel more comfortable in my 642.
After shooting a LOT of .38 ammunition through all of the guns, I felt more comfortable carrying the 642 off duty.
I also apply some bright neon orange sight paint to the front sight every couple or so cleanings, so my 51 year old eyes can see it better under different light conditions. This helps me.
During the CCW classes, I've noticed that a lot of folks that have a hard time shooting their J-frame guns claim to have a hard time "seeing" their sights. It's much harder with the older guns with the really narrow front sight blade & rear notch, too. A lot of them tend to elevate the front sight enough to "see" it, but don't realize that they're significantly raising it above the rear notch ... and then are surprised when they shoot 1-2 feet higher than they think they're aiming, even at 7-11 yards.
J-frames require more practice than larger guns ... but it's possible to shoot these little guns very acurately, with sufficient effort on your part and proper practice.
They're great little guns.
One of the guns I'd like to add to my collection before I retire is one of the newer 649 Bodyguards, chambered in .357 Magnum. I really like my older 649 chambered in .38, and I'd like to have one of the newer models. Even though I find the 642 more comfortable to carry in a pocket ... and I have a Quad-Ported Ruger SP-101 which makes shooting 125gr Magnums very controllable and almost pleasant ... the little steel 649 is an enjoyable J-frame in which to shoot standard pressure .38 ammunition, and I can well imagine the newer model is even better in this regard.
I'm not sure you can have too many variations of the J-frame.