Britt excursion and food & drink costs.

Hi Komandoo lover's, can anyone help? We are going to the island in Feb 27th for 3 weeks 2013 and I have 2 questions.
We are considering going on the britt excursion, can anyone tell me how much it is per person and is it worth the money?
And my second question is- this is our second visit and we are going HB this time instead of AI, does anyone know how much a snack lunch costs, drinks, water costs etc per day for 2 people? We have been offered $50 per person per day to upgrade to AI, which is another $2100, we are not heavy drinker's just a beer & water with our meal.
Ok, one more question- is anyone on the forum going at the end of Feb? If so, see you very soon!

David & Nicole Biggs