Funny you bumped this thread today, I was chatting with my brother earlier today actually and he was saying he hasn't had one shoulder issue since he got his. I realised I hadn't either, 7 months now and absolutely zero shoulder issues. I actually laughed to myself when I realised this, since I would regularly have problems from any very heavy session and just put it down to one of the many 'rewards' of heavy lifting.
However it isn't, and the Sling is still awesome. If you are still interested in Benching Raw though I would at least do some Raw Benching during the week otherwise you will lose bottom end strength.