What I did, and I'm thinking that I made the right decision, is bought a student version. If you're not planning on using it commercially right away, then it makes sense to spend less while getting the exact same functionality. Plus, you can get the unlimited version for about 4-500 bucks, so you can ignore your question about complete vs. unlimited
And the student version plus the upgrade to commercial is cheaper than the commercial version on its own.

About the subscription, I don't know all the details, but I think it gives you access to technical support, more resources (as if there aren't tons of tutorials and extras and everything available already on sites like this), and free updates like service packs (not 100% sure about that one). Oh yeah, and simple license management, whatever that means. In my opinion, unless you're a business or think that Autodesk is the only place to get resources and help, it's not worth it. That being said, I don't have a subscription, so maybe someone who does can elaborate on potential benefits.