I flew BA Gatwick-Orlando and back again last year. And I don't have a single bad thing to say!
Unlike some other PPs, I found the BA staff, both on the ground and in the air, very very friendly and helpful. There was quite a group of us (around 12) travelling to work for WDW for the summer and they made our flight something special! They were very chatty, joking around with us and the passengers around us - they had us all smiling for the whole 9 hours!
One of our group was a very nervous flier too - one of the crew picked up on this on walking past, and made a very special effort to keep checking on our friend throughout the flight. This was very reassuring and really did put her at ease!
Nothing felt like it was too much trouble, and there was no problem asking for drinks etc...
Food was also good - I think it was the first time that I ate a whole plane meal!
Seats were very comfortable and I had plenty of leg room. Being quite tall, this was a first for me! Definitely one of the best flights I have ever been on! Also had on-demand "entertainment" - plenty to keep me occupied, and good music selection too.
I booked this flight as a codeshare with Iberia, so I really couldn't fault it for the price I payed. It was definitely above par as far as I'm concerned, and I will definitely fly BA again in the future.
Enjoy your flight! I think you have made a good choice!