They had what appeared to be the longest closing down sale ever in Coventry recently
They are always having a sale, which should ring alarm bells. Although I might buy waterproofs for my kids there, and my wife got a very cheap fleece there, apart from an occasional bargain, overall its tat. I remember when it was just one shop in Covent Garden, selling remaindered stuff from European manufacturers. Actually there was some good stuff to be had, but obviously that supply dried up and they expanded by buying in stuff and putting their name on it.
If you look at how much their equipment costs, compared with brands stocked in the likes of Cotswold (and they are not always the cheapest), they dont always come off well, and the descriptions are often a little basic. They have a Tor 65 'Expedition' Rucksack
http://www.mountainwarehouse.com/travel/backpacks/large-backpacks/tor-65l-p6694.aspx?cl=BLUE . For £79.99 it has a an Airmesh back, is made from 100% Polyester, and has 'lots of pockets'. I'm not sure what the 'adjustable straps' actually do. And there is no indication as to whether its for women or men (women have narrower shoulders, so tend to need a narrower back system), or the weight.
On the other hand, Cotswold are knocking out the Berghaus Torridon 60 (W)/65(M) for £85 (and you'll get discount off your first purchase if you get one of their free cards). Decent build from a good make, comes in a ND back system (and decent adjustable back system at that), weighs 1.73kg (not bad) and made from a decent fabric. If my daughter needed a pack for D of E, etc, then thats what I'd want her to get. GearZone are knocking out a similar bag from Berghaus for £76. If she wanted something a little more basic, Vango do one for about £70, although a bit heavier. A look around the web would get you a similar Lowe Alpine bag for not much more than the Berghaus, and I found a Macpac for less than £90
http://www.wildtrak.com/product.asp?ID=4140
I always use drybags as a good test of a shop. Exped are standard, so you can tell if they are over-charging, but if they have their own brand, its still good, because drybags are pretty much all the same. MW have a 10-15L (?) one for £8.99. Cotswold are charging £10.95 for Exped (you can get them cheaper, and they are Exped), but Sports Direct (which MW resemble in so many ways..) is knocking out their Karrimor ones for £4.99 for 15L. Personally, I buy the Airlok XT's from Alpkit - awesome quality for the money (13L for £8.50), and even their standard ones are great.
Overall, you can do better for the money by looking elsewhere. Alpkit, Lidl, Aldi, Go Outdoors, etc all have decent kit if your looking, and at better prices. Its not just me who thinks that way - search for 'Mountain Warehouse' on Outdoor Magic - people score it below Millets!