By bournemouth i'm assuming you mean EPTA? (Cabair) i attended that ground school from september to march this year, and i have to say i rate it very highly. instructors are top notch, definately know their stuff (majority are ex mil/industry),very friendly atmosphere, makes workin 9 hrs a day alot easier! a couple of the good ones left recently so i'm not too sure what its like now, but i'm sure its still top dog.
As far as OFT's ground school,never attended it,but i went there to do some flying after my exams - i heard mixed things about it...plenty of people doing it, but from what i hear its not the best around. Definately not the most established school in the world - as some other ppruners have said, why choose a school thats just getting to grips with what they have to teach when you can choose a school in england thats well established and perfecting the way they teach for pretty much the same price? Also, euroflight (the place the GS is conducted) has been dubbed 'The Zoo' (no kidding), i'd find it very hard to learn there with so many people/distractions.
In terms of cost...i got a semi decent room in a shared house in bournemouth for £250/month, not too bad...OFT's housing depends, if you stay in a hotel expect $50/day (£25) or in a shared house $35/day (£17)...do the math, it works out as alot more! and i doubt they have any rooms in the houses left now, so my money would be on you stayin in a hotel.
But anyway, its not my choice to make, i'd investigate both schools thouroughly before making a choice, just beware of the spin some people put on things...good luck!
CS