There is no way to upgrade from one version of Linux Mint to the next. I'm using Linux Mint 2.1 "Bea" (Beta-023) and I find it very usable. The final version is scheduled to be released in a few weeks. I would recommend jumping right in and trying Bea if you're comfortable using a Beta.
Apart from Amarok it's quite stable This beta release is mostly there to let us time to squish things in at the last minute and get users feedback before the official release.
So far only a few modifications have been planned for the 20th.. there's a panel.entries file in / that we forgot to delete And the icons at the top are using absolute coordinates, so they look funny under widescreen resolutions