I've got a MacBook Air, had it about 2 and a half if not 3 years now, it's still like new, 4GB RAM, 256GB Flash Storage ect ect. Well worth the money, I see them as more of an investment.
I always find windows computers get slower and slower over time, easy to get virus' where as mac's don't need security ect.
Think mine was about £1400 but well worth it I think.