Is it worth upgrading to a laserjet? Only if you want waterproof printing What are the consumable costs like? Full set of toner will set you back £200-£300, plus eventually they need new expensive bits (at that stage it is usually best to throw them away). Do they all do double sided? No - most budget ones don't - the one you linked to for instance doesn't.
If you want a budget duplex (double-sided) multifunction colour laser, there isn't much competition for this. I've got one, it's done about 5,000 sides and works great. Beware, they are huge.
I upgraded to a laser for all B&W prints, but kept hold of my old one for occasional scanning and the odd colour print out. Can you do the same? Deffo worth it for the laser. Toner costs about 45 quid but does 2500 pages so lasts for ages and ages.
I've got HP4 thats about 15+? years old ex-college model, size of a small corner table, ink is cheap on ebay and does about 8,000 pages so hardly gets changed much.
I had an Inkjet once, waste of space that it was, every time I went to use it the thing was clogged and the ink was so expensive and didn't go very far, still thinking of getting a kodak cheapo printer so I can have colour prints. but for black and white nothing beats a good laser, if you can actually find a good one that is, modern ones are crappy.
We got a basic B+W laser printer as we were fed up of clogged printheads too. We have kept the inkjet to use as a scanner. A new toner cartridge cost £24 last year and lasts much longer than cartridges ever did. Much more reliable - ours is a samsung, got it reduced from pc world for under £100.