My 0.02c worth on this subject, and if this reads like a put-down of a good, honest question, it's truly not intended that way at all:
1. Sophisticated software is complex; deal with it
2. You get what you pay for (and you can decide how much is too much--it varies with your outlook)
The things that "traditional" CAD packages (like AutoCAD and its siblings) and "parametric modelling" packages like Alibre do are non-trivial and sadly, learning to use them requires effort, just like learning to use machine tools.
I've used traditional CAD (TurboCAD in my case) for over 10 years to produce over 70 complete IC model engine plan sets (starting with all the ones in the AMA Motor Boys Plans book). It is not expensive and older versions are freely available. But the vendor (IMSI) seem to purposely orphan the native file format every 2 versions (eg, V8 will read V9 files, but not V10). For this alone they should be publicly burnt at the stake, IMHO (not an issue if file sharing is not an issue, I'll admit).
The comments re Alibre are spot on (see the Jan 2008 issue of Model Engine News for more observations) and having done 3D and 2D work in both, my feelings are:
a) Alibre IS comparatively simple to learn and will not require re-learning for 3D work if you've not touched it for a few months
b) A simple 2D sketch (like a coordinate layout for a complex hole pattern from some common datum) can be done in either Alibre, or a "traditional" CAD package, but is probably quicker and easier in the latter.
The "try before you buy" philosophy mentioned by someone else is a very sound suggestion, but learning ANY package is an investment in time and possibly $$. And there is the danger of then staying with that package because of this investment (like I've stuck with TC from V3 to V10, but no more ;-).
Read as much as you can about CAD "features" on the Web until you can understand all the advertising promises made by all the different the vendors (and not just the free ones). Then hunt up product comparison tables and make an informed choice from what will meet YOUR requirements, ranking the features. Unless you have lots of time on your hands, I truly, truly, humbly, suggest that while license cost should feature in your choice, it should not be at the top. The time invested in learning the thing will make the cost seem small in comparison and making a bad choice just because it was free will probably bite you later. Rank the availability of documentation, on-line tutorials, dedicated user forums, examples, third-party books, etc higher, and make good use of them.
Product stability should feature high too. Something that crashes frequently and takes your work with it will sour your whole day (regardless of how often you think you will "save" as a precaution). Check the forums for an indication of what other users are experiencing.
< rant mode .off. >
rc
