I use Solid Works. It actually creates entities as surfaces, and then fills them in. I'm still not that great at complex surfaces yet--Every different kind of surface function has different rules about how to use it. Of course I don't use it for surfaces that much, so it follows that I'm not good at it yet.
Solid Edge/Solid Works should, IMO, demolish AutoCAD in mechanical design applications. what little experience I have on it suggests it is more capable and more user-friendly.
I simply cannot understand why, in AutoCAD(2K)...
1. you can make a solid, and explode it into a set of surfaces, but you cannot define an identical set of surfaces and then extrapolate a solid from them.
2. you cannot extrude a solid between defining control contours
3. you cannot (directly) extrude a helix
other, cheaper, EARLIER programs have those capabilities.
*shrugs*
maybe Autodesk adde those caps to the app in later releases, but I don't have the kilobux needed to keep up with the latest-greatest.