Movie Studio Platinum (
Vegas Movie Studio Platinum up to and including v. 11) is a "consumer" version of
Vegas Pro. It lacks several features of the "pro" version and is priced accordingly. See the Sony Creative Software site for the version comparison table.
As
sanlyn tells you in another thread, MSP 12 is probably good enough for you. You'll find a downloadable trial on the SCS site, but you cannot buy it direct from them any more. It seems to be available at greatly reduced prices online elsewhere still though and you'll be able to use your v 12 license to upgrade at a discounted price later, if you so wish. VMSP 11 is only 32bit, whereas MSP 12 and 13 are available as 32bit and 64bit. I strongly recommend using a trial version first, so you'll get some idea of the "ease of use".
There's a very good independent review of MSP 13
here , which also advises you of the differences between v. 12 and v. 13.