With yesterday's release of Umbraco v4 RC2 I couldn't wait to get a
production site upgraded and ready to go. The install/upgrade
went smoothly and within minutes I had the new UI displayed - it is
quite beautiful (see below). Next, a few minutes spent
dropping in the required assemblies and user controls needed for Commerce for Umbraco - then a bit more time
editing the configuration (yes, this part of the Commerce install
sucks and we're working on it!). With 20 minutes of effort I
had a beautiful new install of Umbraco v4, commerce enabled and
ready to roll! First thing I noticed, after the new icons,
was how fast, smooth, and responsive the UI is.
There remain a few minor issue with v4 (list here) but no show stoppers and I highly
recommend you begin using v4 for all your sites as soon as
possible. I know I can't wait to upgrade the motusconnect.com. and the planetmold.com site along with others.

The members integration is flawless and 'just' works with off
the shelf ASP.NET membership controls. So, if you've been
waiting until Umbraco v4 was stable - now's the time.
-Paul