I'm with a few of you on this one.
Float bag for 10-20mins, add tank water, float more, drain some from bag(Into sink, not tank) so I can add more tank water, float more, drain more from bag, add more tank water... Usually just a few times, then I remove bag, net the fish and place in the tank. I have had fish eat food minutes after doing this so it can't be *that* bad. These were all fairly inexpensive <$40 fish, and most are considered hardy fish.
However when I had SW fish, I did a sort of drip method. I just put the fish in a 5g bucket with the water from the bag, then added a cup of tank water every so often until there was more tank water than bag water left. Then let that sit for a while, then netted the fish and placed in tank. Discarding the water from the bucket.
Now, if I were dealing with Rays (Which I will tackle some day hopefully), or other highly expensive sensitive fish I would do the drip method hands down. Way to high of a risk for the sensitive types and especially financially when you consider even a basic Ray is 5x the most I've personally spent on a fish.