I love my 340m&p. Yes the recoil is a bit harsh with 357, but Every time i shoot full bore 357 out of mine i get a giant smile on my face. I rented an lcr before I got the 340, and it does have a slightly better trigger, but I did feel like the stack on the trigger was pretty bad. Out of the box the trigger on the j frames are general horrendous, it did not smooth out until after i dry fired it over 1,000 times( this will also work out you trigger fingers). Either one of them will work well for you, but the 340 is just more fun for me.
Eric