Service wise IMHO most of the liquor outlets are generally pretty good. It's a monumental logistical challenge to pick dozens (hundreds) of liquor orders on a busy day and deliver them all properly. Errors happen, since its the ilons, but I'd call them randomly distributed, none of the big outlets has a name of being significantly better or worse than the others. I've got lots of my own anecdata, but by and large it seems to be a pretty even split. Helps if you are getting your stuff on a non-weekend day!

If you're choosy - and who isn't - and you've got time, rent a car to shop and see the island. It is way cheaper than taking taxi's, and driving around is fun, and it makes shopping way easier. Stops the problem of getting unwanted substitutions, since you choose your own.

Tico has a nice retail store just up the road from the Riteway, and Riteway has a decent selection too. I know Tico has Tanq 10, but you may have to go to the CC warehouse on Wickhams cay for Tito's.

I saw more of Tortola driving around than I ever did from the water. Some places like Bananakeet are hard to reach without a car, and definitely worth seeing. Same goes for Virgin Gorda, you'll never get to Hog Heaven without transportation and its worth it.