punctuation - Is this dash correct?

I’m hoping someone can give me some feedback/advice on the dash below.

The site also supports a mobile
version that allows you to easily
check whether a book is in your
collection—a feature inspired after
purchasing already-owned books one too
many times.

I guess I could also split this into two sentences.

The site also supports a mobile
version that allows you to easily
check whether a book is in your
collection. This feature was inspired
after purchasing already-owned books
one too many times.

Is the first version is correct, and if so, is it preferable to the second?

This link makes me think it's correct, but I thought I'd ask the community; I always seem to get fantastic feedback here.

Answer

The first version is correct. You've used a dash to separate the appositive from the main sentence, which is acceptable. Usually, this is considered better than the second version; one independent clause is better than two, stylistically speaking. I myself would probably have used a comma instead of a dash, since I think commas give a much nicer flow.