I did steeks on a sweater for the first time last fall. It went quite well although making that first cut into the knitting is pretty scary. I used Brown Sheep's Lamb's Pride (wool/mohair blend) and it holds together well. I used the reinforcing stitching, but did it by hand with sewing thread instead of using my sewing machine so it'd be more stretchy. There's a nice series of posts by Eunny Jang about steeking here:

http://www.eunnyjang.com/knit/2006/01/steeking_chronicles_the_should.html
http://www.eunnyjang.com/knit/2006/01/the_steeking_chronicles.html
http://www.eunnyjang.com/knit/2006/01/the_steeking_chronicles_part_ii.html