Hi IWYS,
I work for a company called KingsBusinessTransfer, which specialises in sale / acquisition of businesses, specialising mainly in retail and food. (We've sold more Bargain Booze outlets than any other broker on the market

...okay okay, that's the last of the subliminal selling, I promise!)
I won't go over what's already been said, but to add to the very good points made by others, here's my bit:
We sell lots of franchised businesses (Nisas, Subways etc) and Bargain Booze is by far our most popular franchise - I think that's pretty telling in itself, people aren't usually wrong en masse! I'd also really recommend BB with the Thoroughgoods element- Grocery stores are one of the few industries triumphing at the moment (boring sales bit from IGD: Convenience stores are the fastest growing sub sector within the Grocery market, and grew more than the Grocery market as a whole last year. They enjoyed a 4.9% sales boost too, and sales are expected to grow considerably over the next 5 years.)
Someone said that people are unlikely to be loyal to where they buy their alcohol- and they were right - but people are much more loyal about where they buy their groceries.
Also, (and I don't mean to offend anyone by saying this!) a Bargain Booze is one of the easier franchises to run, as opposed to say a Post Office (where you have to pass an exam before you can buy one) or something like a McDonalds or a Subway, where there are lots of processes to be learnt, and new staff will require lengthier training. There's obviously all the other advantages of franchising; training etc etc.
As for the rural element you mentioned- I guess that's a case of what other competition there is in the area etc. Also, be wary of the reaction of locals - I don't live anywhere particularly rural or picturesque (far from it, I live just outside Blackpool!!) and when a Bargain Booze opened in my area there were a few petitions. The Bargain Booze went ahead regardless and has been successful, but if by 'rural' you mean tight knit, maybe it would be a good idea to test local reaction before you commit to anything?
Finally, from a personal rather than a business perspective, my next door neighbour owns 3 BB & Thoroughgoods sites, and he couldn't rave about them more. He also owns a Nisa, but says he much prefers Bargain Booze.
Good luck with whatever you decide.
Laura