Unless you are cutting a lot of PCBs, and I mean a lot, I wouldn't bother with any saw, a saw sounds like a cool idea sure, but it's messy, noisy, and troublesome.
Just use a carbide tipped laminate/tile cutting scribe/knife...
![](https://2ecffd01e1ab3e9383f0-07db7b9624bbdf022e3b5395236d5cf8.ssl.cf4.rackcdn.com/Product-1600x1600/026d6902-7680-4340-9943-84b13af4dab9.JPG)
available from hardware stores. Use a pair of rulers clamped down to form a slot-guide over the PCB where you want to cut, scribe it 3 or 4 times, flip the PCB and do the other side, now it will snap just like a DIY v-score.
Here is my cutting jig (hook knife is what I used to use before I had the carbide tipped cutter)...
![](http://i.imgur.com/f9l9vBO.jpg)