All machines tend to slow with time as folk fill the drives or add more stuff. I have a 10 year old Compaq R3000 and it's as fast as it was new and the OS has never been reloaded and this is just one out of dozens at the office that don't show any sign of what you asked about.
The Macbook Air is written about very nicely by CNET so I won't duplicate that here.
I need a new laptop for university. I was looking to get either a Dell XPS 12 Ultrabook (Converts into a tablet) or a 13inch Macbook Air. Both have the same specs ( 4th gen i7, 8gb RAM, 256gb SSD) , and cost the same after warranty and stuff. Also, the Dell has a better display, but the Macbook lasts longer (12 hrs compared to 9hrs). The dual functionality of the Dell (touchscreen) makes me want to consider getting the Dell. However, I've heard OS X is a plus point for Mac. I will be using my laptop for normal school work (docs, web browsing), I sometimes (rarely) use Photoshop, however I still want a laptop that runs very fast (almost no lag) and has excellent boot times. I will -definitely- be using it throughout university ( 4 years + ). Hence I need something reliable.
1. Do Macs tend to slow down less than Windows laptops over time (i.e.Macs - OS X more reliable), considering both of them have SSDs (Windows 8 vs Mac Os X ) 2. Could you suggest what I should get? ( If any of you have these laptops or just any suggestion)?