I like my 638. I don't carry it anymore, but I simply can't part with it because its a great shooter. The sights are perfect at 10 yards. Recoil is stout because of the small grip, and light weight. Its surprising how small it really is, when compared to my other snubs.
A word of caution. Check speedloader clearance with the factory grip. It will lock up an HKS speedloader tight, and you will have a hard time freeing the speedloader. I had to drastically relieve the grip to get adequate clearance. I'm surprised S&W doesn't make a change to the grip for that reason.