Still a bit buggy. Rated 3 out of 5 stars

This is what I was looking for. But it still has a problem with dictionaries that are very similar. In my case it repeatedly uses the British dictionary when really I need the American one. Maybe there should be a way to set the preferred order in case of there being the same amount of errors in more than one. And another open question is what happens when the right dictionary just lacks some words that a wrong one has included.
Another thing I wonder, is why it seems to only check part of the text, instead of all of it. It seems to depend on the cursor position. Please remove that, or at least let me disable it.

If those things would be fixed, it would be perfect though.

This review is for a previous version of the add-on ( 

Thanks for your helpful comments.

Regarding the AE vs. BE problem: I'll think about it — it's somewhat difficult to make everyone happy.
Why is the addon only scanning part of the text? Well, first of all that's a performance consideration. It's just too expensive to spellcheck everything all the time. It would of course be possible to use "cached" spell checking results but I'd rather keep the code simple. Additionally, I write a lot of bilingual text, so I want the addon to change language when I switched languages in writing e.g. an email.
The cursor position things are an experimental addition in 0.3.1 (beta). In 0.3.0 you should not see something like that. Taking the cursor position into account is crucial for writing bilingual text and for people who have predefined email footers. An option to disable it seems sensible though.

I can only dedicate a very small amount of time to developing this addon. If you are a developer, feel free to work on these issues; feel free to contact me with further questions.