There are a lot of circular saws available on the market.  Festool has two main types of circular saws, but they have a twist to their lines of circular saws.

One of the coolest features is their plunge cut ability.  The saw also leaves very few splinters and prevents burns.  What I like best is the ease of changing the blade. We have all changed circular saw blades before and we know how this can sometimes be tough.  Festool has a Fastfix system that makes changing a saw blade a lot easier. 

As with their router, their circular saw has the MMC feature which produces a constant speed under load, which produces a faster and cleaner cut.  Festool saws also have a guide rail that will glide along the rail to produce a straight cut every time.

All in all, this is one great circular saw.  Lots of power and many features to help the user have more control