Mick Hardy
Initial testing of Sony Vegas Pro 13 with TandemVids has been successful. You may wish to delay a few weeks until testing of the next TandemVids release has been completed. The YouTube upload functionality has been rebuilt from the ground up to support the new Google+ accounts. The next version is finished but testing is ongoing.

Vegas Pro 13 is here! Save up to $150 through May 31!

Vegas Pro 13 for $500 USD 

Vegas Pro 13 Upgrade for $150 USD 

I'm pretty sure you can buy a brand new copy of Movie Studio 13 for $50 USD  and then use this offer to upgrade to Vegas Pro 13 for $400 USD . This gives you Vegas Pro for $450 USD, which is a significant discount from the $600 USD standard pricing. I know someone who did this last time the offer was on and it all went through fine but I can't guarantee it will work this time.
Mick Hardy
There is currently an issue with Vegas 13 during the archiving process. A new message box prompt is shown during the archive process. It means you need to click OK for every video.

I'm looking into a workaround but if you're thinking of upgrading, I'd stick with an older version.

The Sony Vegas message is "“Some of the media on the timeline was not trimmed to preserve quality.” It can be ignored but it's annoying.