The regular (R) version has a tap control feature to control streaming and phone calls. I haven’t had much luck with it, but some people like it. The RT version has a telecoil, but no tap control. The only downside I can think of for the L is that its charger is much more expensive, so if you want a spare, it’s going to cost you. The Ease charger that comes with the R and RT is under $100 on ebay, and they can use old Combi chargers that go for $20.
For the waterproofing, I haven’t tried it, but a common issue is that the receivers aren’t waterproof. They’re cheap and easy enough to replace, but the bottom line is that you still have no functional hearing until that’s done. It’s not like you can go swimming with the Life and expect to hear everything while you’re in the water (though you may be able to rig up a mold so that actually works).