The CMD riggers are super nice riggers and don't really have any downsides in terms of performance. The only downsides I know of are their price compared to other riggers and build time. But, as the saying goes "you get what you paid for." CMD's are second to none IMO.
However, shop around and take a look at what people are running in your area. Its a lot easier setting up a rigger when a club member or friend has the same boat and your not familiar with riggers. Some riggers are very touchy and difficult to set-up. Their reward can be greater, but the frustration can end the project quickly too. Others are simple to set-up, offer great performance and run all day long finishing every heat.
If this is your first rigger consider the Roadrunner, Cajun Bullet and G-Force from Bob English.
Tyler
(BTW, I own four CMD riggers so I am a bit biased)