I like the PanaVise options. I have one large base and can swap in two different heads as needed. I have the model 350 (base & vise) and swap in a 203 vise depending on the board I'm working on.
I have a few different ones. But the one that gets used the most is the Panavise Jr.. It is for most small-to-medium sized boards, including Arduino shields.
I got the Dremel Multivise. It's got a nice sturdy base that clamps to the side of your workbench and the vise section can be removed and used as a clamp or used freestanding on your bench. The base also comes with an adapter ring that holds your Dremel (or other branded Dremel-like tool).