I went lead-free a couple of years ago and have been mostly pleased. Killed several deer with Barnes TTSXs in a .257 Ackley and four last winter with Hammer HHTs in my 25RPC. The Barnes gave one blood trail that Ray Charles could've followed and one that didn't leave a drop for 50-75 yards. The Hammers seem to create more internal damage (probably by virtue of the petals shedding) resulting in shorter track jobs but more sparse blood trails.
From what I gather, going lead-free is unlikely to have a population-level conservation effect outside of unique areas like the condor recovery zone. I just like the idea of ingesting less lead than more.