OK, I'm driving so I may not capture all my thoughts on this subject that I'd like...

First off -- adding a loop WILL change your draw length!! It may not change the BOW'S draw length, but it will change YOURS. Adding a loop will increase the distance between your bow hand and your anchor point; assuming you keep your bow hand the same (including the relationship of the grip to the bow and eveything else), it WILL move your anchor point rearward. It HAS to; if it didn't, we could assume the loop was ZERO inches long -- which in turn means you didn't tie a loop on! Add a loop of ANY length, and it moves your anchor point rearward. To compensate and keep the EXACT same anchor, you'll have to decrease your dl, if only slightly, depending on the length of the loop.

That's why I like to tie mine as short as physically possible. Look at my "How to tie a d-loop thread" pinned at the top of the tech forum, and you should be able to start tying your own within no time.

The good thing about loops is the ability to fine-tune your anchor point without placing the bow in a press to twist/untwist cables. Now on my 3d bows, I do both: I like my loop a bit longer because I'm shooting a hinge or a thumb-trigger style release (I regularly use both), and I can't afford for the loop to be TOO short and impart torque on the connection point. Therefore, I use a longer-length loop and shorten up my dl by close to a 1/4".

Perhaps one of the most practical benefits of shooting a loop for a bowhunter is the ability to let down after being at full draw if needed without the arrow popping off the string due to nock pinch. Look at the last picture in my d-loop thread and you'll see why it doesn't pinch the nock as much. The tradeoff, as you rightly mentioned, is it IS a bit harder to hook up in the moment of truth. I know; I shot "off the string" for more than a decade" and you're right in that you can just hook up ANYWHERE on the string below your nock point and simply slide your release up. In fact, I've gone to exclusively using flourescent coloring for my loops these days as it helps me hook up even easier in low-light conditions.

There's also no center-serving wear on your string when using a loop. It'sfar easier to cut off a loop and retie than to serve a whole new center section.

There's several other benefits as well which I won't get into... but DON'T use one of those junk metal ones. Just go ahead and throw all those away.