We've got 16 Lewmar rope stopper/clutches. We like them for what we use them for -- but I've not used them for sheets.

While you "can" release the load of line stopper -- I've been told that it really isn't a good idea to do so repeatedly under load. At higher tensions, they can "blow" up being stressed repeatedly like that.

I've found that many times, you really want the sheet not to "blow" but rather to be eased a bit. Then having the variable turns on the block that you can either leave in place or "blow" seem to me to be a better general practice.

I haven't found a sheet stoper that doesn't add a bunch of friction. If you use a stopper with a line range, then pick a line that is the smaller diameter to minimize the friction.

My other grip with line stoppers is that they tend to get hung-up with a curl or knot in the line. I've found that over time, you have to be much more sensitive to flaking the line vs. coiling it with line stoppers.