1) No, most cases it would be even a bit slower. Like probonic said, whed using shared hosting you can use full power of the server when needed, and with VPS you're limited with whatever MHz you paid for. (Yes there is 'burst usage' practice, but it works well only if the server isn't too oversold.)
However, if you use intensive scripts - a shared host might kick you out for overloading server and affecting other customers. In case of VPS, you can use 100% allotted CPU all the time - they won't care, it's what you paid for.
2) Again, agree with probonic that it mostly depends on a type of site you're tunning. If you have a live blogging site with many users - I'd advise not to go with minimum package, better start with 256Mb or so.
3) If you have some control panel installed, it's mostly the same, adding a few features. Without it, you have to have some decent Linux knowledge, or you'll go through lotsa pain and end up hiring experts to get you giong.