I've imported three blogs from Blogger and have had issues with each import - all different reasons! Once I'd ironed out the problems, the imports ran very smoothly indeed.
However, it did take a dig and some tinkering to get these to work. The problems I encountered are commonplace. Some mention of these in the Blogger Codex would be *hugely* useful.
I'd even be happy to write it up if some editory-person was prepared to pop my text into the Codex.