I guess it depends upon how much tweaking you are comfortable with. A £300 Chinese copy can produce excellent results, but may need some tlc to get printing.

Don't forget you will need some slicing software (free works, but some paid for software is easier) and I would avoid any printer which ties you into a specific brand of filament.

A heated bed is a must for abs, but dual extruders are not really required. Think about bed material and fit some print tak or similar, as it will help with bed adhesion and make printing easier.