I've bought a couple of these, one for the missus' car, one for mine.
I like the idea of rear-facing up to 18kg (approx. four years) as it is inherently safer for wee'ns in the event of frontal crashes.
They are also front-facing if you prefer, with a three position recline in that mode.
Anyway, I managed to get one on sale for £70 at Littlewoods (though I only paid £20 as I had a £50 voucher) but they've gone up to £90.
Then I spotted these at Argos and got my second one yesterday.
Decent deal I think and much cheaper than Amazon where they are about £85 upwards.