Having just read it a few months back, I recommend the John D Smith edition, which is the only 'complete' translation in a single volume. I promise you, that you won't get any other translation in a single book.
There's a reason I put 'complete' like that: the filler parts of the Mahabharata (and there are a lot) are summarised instead of a whole translation. If that bothers you go for the 10 volume Bibek Debroy edition.
Lol, fuck that. Unabridged costs in excess of £200.
Will ask /r/hinduism too.