I've never used any sort of CAD design stuff until Sketch-Up showed up on the market and because it was free and seemed cool, I dove in head first. It was a little frustrating to use at the beginning but once you learn its nuances, you can generally get done what you want with little issue. I think whatever software route you choose, as long as you spent some time to learn it, you're likely to be generally happy with it. One boost for Sketch-Up is Dave Richards, a master in SU, and who regularly peruses SMC and pretty much answers all SU questions. He even put out a little video that really opened my eyes into using SU more easily (it was one I paid for...on sale an X-mas or two ago).