To go just for an MPhil without PhD will probably not add anything to your CV.
An MPhil is seen by many as a poor relation to a PhD. It's what's awarded when a PhD candidate has failed to make an original contribution or new data to their field.
A taught Masters is a different matter, in that clear skills are being added to your repertoire. This makes a taught Masters an easier sell and better justification of your time in education and out of the jobs market.
I personally would give just an MPhil a miss, the one exception being if it was as part of a teaching company scheme with a placement in industry. With a teaching company scene, you're at least picking up real saleable work place skills.
Ian