I've been tying on a HMH Standard now for a couple years. When I first started tying flies I started on a cheap vise that came with a kit. I soon upgraded to a Regal which I used for several years. But after tying on the HMH I couldn't go back to my Regal again so I sold it on ebay and picked up this HMH Standard C-clamp. There are a couple features about this vise that make it a worthwhile investment.
The vise is simple and solid. It doesn't have a bunch of levers and bars and other parts sticking out everywhere like some other vises (Griffin is famous for this). Having a simply constructed vise has helped me speed up my tying and I don't waste as much time. The vise is made of solid steel and unlike other vises on the market, it does not incorporate a lot of plastics and rubber which end up wearing out over time. The cam mechanism is extremely powerful and can hold a great range of hooks (2/0 - 20 with the standard Omni jaw).

There are also optional jaws for the vise which can be changed out by just unscrewing the jaws. It takes less than a minute to take out the existing jaws and put a different set in. The optional Micro Jaws hold hooks sizes 18-32 and the Magnum Jaws hold hook sizes 14-10/0. One of my favorite features is the optional Tube Vise Converter Jaws (see pic below). The converter just screws into the vise like any of the other jaws do and these "jaws" hold the mandrels to tie tube flies.

...read the full guide with pics here