I have been with Boots Opticians for now for the best part of 3 years, and not once have I ever thought of moving.
I have both glasses and contact lenses from Boots. The best thing about receiving your contacts from Boots is that they will give you free eye tests and free contact after care appointments to make sure your eyes are in good health. I get my daily disposable contacts from them every 3 months via home delivery, I get about 90 pairs which last me more than 3 months, so I always have some spare. I only pay about 16 pounds a month for them too! Recently the sent me 3 month's worth of their new hydrating contact lenses for free as a trial! And I can upgrade to them for only a few extra pounds a month which I shall be doing as they are great!
Another good thing about getting contacts from Boots is that they will give you a yearly £50 voucher to reduce the cost of a new pair of glasses (which can still be used with their 2 for 1 deals) or you can use the voucher towards the cost of your monthly contact lens bill.
Overall I'm very happy!