I use a couple of them. One that I got from Garret Wade has an additional fitting that allows for positioning around an additional axis. But it's a lot more expensive than the regular parrot vise. I was lucky to get a gift certificate from my son that helped to make it affordable. If you want to look it up it's called the Ultimate Versatile vise. Here's a couple of pics.
Review: The Green eBay Model (there are no markings on the vise) does the job. However, the Shop Fox vise is a higher quality vise.
1. There are more surfaces ground smooth on the Shop Fox. The jaw sides, the mating surfaces for using the vise sideways. The jaw guide rails also have finish that is not ground smooth on the eBay one.
2. The fit and finish all around is slightly lacking on the eBay Model
3. The lower adjustment arm is mounted with a spring pin rather the peened metal pin on the Shop Fox.
4. The jaws on the Shop Fox are roughly 1/4" taller.
If I get another one - I'll go with the Shop Fox.