Hi,
All kitchens are basically a rip off, a few grands worth of chipboard. Magnets have the best kitchens off the shelf probably, fitted 100's. Howdens have fairly good units but can be expensive with worktops, and accesories. Wickes aren't great, crap units made out of poor quality chipboard, worktops are probably the worst quality soft chipboard. B and Q units are ok 18mm chipboard, worktops aren't even moisture resistant chipboard. To be honest, you're probably best off having your kitchen supplied and fitted by a small local kitchen fitter (someone that just fits kitchens) they usually get the best prices on kitchens because they buy the most, and know which companies do the better deals on which parts. Most parts Units/Worktops you can always find cheaper online, especially higher end ranges, solid timber worktops etc. Or order direct from the manufacturer rather than through a middle man DIY retailer or Builders Merchant/ Howdens etc.
Hope this helps