I recently wrote a post (WordPress.com versus the new Blogger) in which I compared the feature sets of the new Beta Blogger with the freely hosted blogs available on WordPress.com, and also what new features are being rolled out in the new Beta Blogger.
This recent post from the Googolians blog makes some interesting points regarding whether to move our old blog to Beta Blogger or not. It sounds like problems have surfaced with logging in, template corruption, and scarily, lost blogs. Apparently some users who have acted on the option to convert their blog to Beta Blogger (most Blogger are not yet presented with this option) have had their blog disappear! The Real Blogger Status Beta blog also has a list of some general design deficiencies which my cause you to think twice about migrating your blog.
This is an early beta version of what one hopes will become a solid service, so hopefully these issues will be resolved over the coming weeks. On a positive note, it looks like raw HTML editing is now available in Beta Blogger. I will be looking forward to switching despite the problems if only to get rid of the spinning publishing triangle of death.
A valid idea is being proposed on many blogs, and it is one that I am likely to experiment with. Create a Beta Blogger mirror blog for your regular Blogger blog, and just post your content to both blogs for the time being. This will give you a chance to play around wit the new features (sidebar widgets, categories, etc.) without subjecting yourself to the problems that are surfacing with Beta Blogger.
WordPress, anyone? That still seems like a better choice for most people right now, but time will tell.