I've used it a lot for general purchases (esp books and DVDs), but used it for the last year for buying strips and lancets for my accu-chek aviva.
But I will need some more strips soon, and when I checked last night prices seem to have gone up considerably (I managed to get 4 boxes for £25 about 6 months ago, now 1 box seems to be £15 or so, inc P&P).
I did get one box that gave me slightly suspicious results, so I concluded that it probably hadn't been stored properly, but overall the experience has been very positive.