Rory was also not a good one for the alpha roll. Some of the posters might remember rory was a nightmare puppy - very dominant, alpha and all that...she used to bite a lot (as in, puppy bite that became quite persistent and painful), she used to physically harrass me. (I know it sounds stupid now, at the time, it seemed very serious). She would lunge, snap, bite, etc. and not give up - this would go on for a half hour period with repeated corrections - she was like a robot programmed to maim! (This was at the age of about 16 weeks!)
We got a lot of advice from books, websites, other doggie people and all that; the alpha roll was recommended. We did use it and sometimes had some success - but often, it would make her an absolute dog possessed and she acted like she wanted to kill you when you did it(and after). Some people will say I wasn't doing it right or whatever - maybe that's the case, but I think really, it just wasn't suited to Rory. (We also used to use the scruff shake, that didn't make her mad but didn't have as much effect either). A few times the alpha roll seemed to shock or scare her but other times, it made her more determined to 'get' you once you let her up, after she stopped struggling. (And yep, I was holding her down for up to 5 minutes too).
Other anti-dominant tactics we used were staring down, spitting in her food, eating first, going through doors first, etc. Behaviour corrections were yelling NO, hand down throat for puppy biting (we found this MOST valuable, recommended by GAD), yelping like a puppy (only served to make her more determined) and isolation for 10 minutes. (Hated it, HATED IT, HATED IT)
The thing that ended up working was dog training school. While it didn't specifically address Rory's dominance problem, it addressed the dog/owner dynamics simply by repeating and repeating commands and exercises and showing the dog they need to do what you tell them. It not only taught her to drop really well (which we have found invaluable), it just made her an all-round better behaved dog. The issues we had with her soon diminished and have long disappeared.
But, like Jeannie said - if it works on your dog, cool! If it worked on my next dog, I would use it when necessary! Just not on Rory. Well actually, maybe if something bad cropped up, I would use it on Rory these days, as she is a different dog so would probably react much better to it.