You might like to pop over to
amsat.orgThey have members who been building low cost satellites or experiments for satellites for some time, including cubesats.
In my limited experience, there are a bunch of very helpful, very knowledgeable people involved.
Things that matter are how long will your cubesat be in orbit, what height and orbital motion, etc?
The power budget is quite low, and radiation hardened electronics may be important. How long have you got to build the system?