I don't have either pistol, but they are both J-frame revolvers, DA only. J-frame rimfires have a heavier mainspring than other J-frames in order to ignite the primer reliably.
So, the trigger pull on both are probably going to be very similar, both in length of pull and strength of mainspring.
The rimfire J frames, in fact all double action revolvers in rimfire, have to have a heavier mainspring than their centerfire counterparts. The rimfire is harder to ignite.
I've read some comments about the Ruger LCR 22 LR, saying the trigger is especially nice. Any reason to expect the LCR 22 to be an easier pull than S&W's 351c or 43c...?
I have not compared the j frames, but I can tell you that 48s have trigger actions that are quite a bit heavier than 17s. So maybe the same is truth for their smaller brethren.
I've read some comments about the Ruger LCR 22 LR, saying the trigger is especially nice. Any reason to expect the LCR 22 to be an easier pull than S&W's 351c or 43c...?
The LCR trigger is probably what you are looking for. I prefer the heavier feel of a J-frame and the positive return of the reset. The LCR trigger feels so light it's almost mushy, I just couldn't warm up to it.