I have a Cabela's laser boresighter, and it's saved me some time (not to mention ammunition) at the range.

True, you can't sight-in the rifle with it, but it was a big help to me with boresighting; got me to within a couple of inches, so when I got to the range, it only took a few shots per rifle to get it zeroed in.

If I only had one rifle, I'd spend the money on ammunition and range time, but since I've had a few rifles to boresight, it's been a big help.