RE: shooting directly off the string with a release
Having just switched to shooting from the string after reading a bit about it last summer, I can honestly say I see little difference in accuracy. I'm shooting as well now as I ever have, but I've also fine-tuned things a bit more, and changed what I consider "acceptable," during the last year or so. For me, I like the loop in that I think it allows for better "nock" travel, but I cannot prove that. It just seemed that I was able to tweak set-ups quicker using a loop vs. using a nock set, but again, that may just be personal experience/preference.
One of the big reasons I resisted putting a loop on was that I was afraid I wouldn't be able to quickly attach to it in the "heat of the moment" when a deer was approaching, however I've found that it's really not much of an issue at all.