As a 239 owner myself, I have to tell you that it might be the caliber. I just got back from the range, went with a gun smith friend, and we shot my 239 9mm with Crimson Trace.
He liked it, but we were commenting that it would probably be pretty snappy in 40 caliber. I really like my 9mm version. I can keep the groups within 2" at 21 feet with the Crimson.
As far as the sights go, I also have the night sights. You can get them swapped out by a good gun smith. My buddy, who also lives in Michigan, can install and align new sights for you. If you're interested, just send me a Private Message. He is an FFL dealer, so you can send either just the slide or the whole gun.