I just want to add to this...
Previously I stated that the Lite coat was good enough to make high master with, and while that still holds true (I've shot a few high master scores with it since I posted, and I'm one match away from upgrading), I picked up a hardback coat and I'm not going back to the Lite coat.
The hardback gives you more consistent point of aim shot to shot when standing, where the Lite coat I struggled a little getting it "set" every time as it seems to slide around a bit. Both coats reward you for a good hold, and neither will hide a bad hold, but the hardback is just better at helping you to stand very still.
The Lite coat leaves nothing on the table during sitting or prone however, as I've been able to hold a 199 average through the rapids over the last 6 months. I've shot a lot of clean strings with high x counts, and the shots I do miss are me, not the coat. I fully expect 100 5x strings at 200 & 300.
In my opinion, if this is going to be a sport you participate in for the long term, I'd go for the hardback. You may never want to compete on the national stage, but if you do, you'll want the advantage that the hardback offers. It may be only worth a few points if you do your part, and worth nothing if you don't, but it's still something I recommend.