As a printer the rx685 looks good, of course it's an all-in-one which has to be a trade off in the long run especially if the price is kept low. Personally I don't believe in lumping technology together, when one nit breaks you've pretty much lost all of it, but at £99 it's not going to break the bank either way.
Steveo the r800 is specifically a photo printer, with 7 inks including blue and red according to the review I just read, in terms of print quality the rx685 won't beat it, but it might come close enough for your purposes if you're short of cash.