I use DeltaCad which is a simple 2D Cad program. I found it relatively easy to learn but is powerful enough to do complex rendering.
http://www.deltacad.com
Recently I decided to try (for the 3rd time) Sketchup. This time, after about 30 hours of head scratching and watching tutorial videos, I've had some success. Here is a photo taken in my shop of a completed instrument called an Ottavino.
Here's my Sketchup rendition of the same instrument.
The rendition came out pretty well but it begs the question - "is it worth the time". So far, my answer is no - especially if your project contains a lot of curves. Using Sketchup for drawing curved surfaces like the curved side of a piano or harpsichord, or the front of a Bombay chest is far from quick and simple. Using a Cad program like DeltaCad such a line is simple to do by using a spline line which is fully adjustable. On the other hand, a 2D Cad program will not let you see all sides of your project like a 3D program like Sketchup will.
My other concern is with accuracy. I took the dimensions for this model directly from my Cad drawing. Because I need full sized plans that are very accurate, I use decimal measurements rather than fractions of an inch. A few thousandths of an inch can spell the difference between success and failure when making a musical instrument. While Sketchup allows decimal measurements, I found that parts didn't line up correctly even though the measurements were correct. The problem could be due to my lack of a complete understanding of the program, but, then again, maybe it isn't.
In reality it's a moot point for me because the free version of Sketchup does not allow you to export full sized .dwg files that are needed by my print shop to print out the full sized drawings. The pro version does but it's not worth the cost of the program. So, for me, the basic advantage of Sketchup is the ability to see your design in 3D from any angle.
The good news is that Sketchup (basic version) is free and DeltaCad has a free, full featured Demo that you can download. I think the program is about $30.00 should you choose to buy it.
Why not try them both and see if either one fills your needs?
Ernie