Whether it's worth it to you comes down to a few things:

- Are you miles rich, or would the extra miles spent in first potentially impact your future redemptions?
- Have you tried BA first before? How much do you value more attentive service (usually - I've had this all the times, but not everyone has)? Would you like to access the Concorde Room at LHR?
- What aircraft is your flight operated by? Some people prefer the upper deck of a 747 to F as long as they can select one of the better seats.

If I was redeeming I certainly would go for F because I appreciate the smaller cabin and the better service. If spending the miles won't cause you to miss out on a future opportunity and you've never tried first before I'd give it a shot.

Then in future you'll know whether business or first represents best use of miles for you.