Go for the absolute maximum spec you can afford. Prioritise RAM and storage over CPU.
(sub Mac Pro, Apple's GPU options are pretty shitty these days; even the MacBook Pro has a gimped integrated graphics card. However, unless you have eyes on gaming or serious 3D modelling, you don't care).
The screens are very nice indeed. Very nice. Indeed. Very. The retina screens add to the niceness, but whether they're worth the premium of moving from the Air to the MacBook Pro - well, you should try them out and decide.
Bear in mind that upgrade options on Apple's current laptops are brutally limited.
I.e. there are none. You get what you buy and that's it.
So choose accordingly.
ETA: Things that Apple do really really well on laptops:
* Keyboards - not mega-standout, (my new Dell Latitude work lapper has a keyboard that's on par, albeit not backlit) but they're really nice
* Trackpads - seriously, best trackpads ever
* Screens
* Battery life
Things that they don't do so well:
* Not blowing a planet-sized hole in your bank account
* CPU/GPU performance
* Limited RAM and no upgrade path means futureproofing is limited
* Limited storage and no upgrade path means futureproofing is limited (bear in mind that according to MacRumors, a clean install of Mavericks takes 15-20GB; that's a fair chunk of a base 128GB SSD, which of course won't have a hundred and twenty eight actual gigabytes of space)
* If optical disks matter to you, you need an external drive. Note that if you ever want to boot from an operating system DVD, you almost certainly need the ludicrously expensive Apple SuperDrive (roffle $80 option roffle; I bought a Samsung USB dual-layer DVDRW for £20 last year)
(sub Mac Pro, Apple's GPU options are pretty shitty these days; even the MacBook Pro has a gimped integrated graphics card. However, unless you have eyes on gaming or serious 3D modelling, you don't care).
The screens are very nice indeed. Very nice. Indeed. Very. The retina screens add to the niceness, but whether they're worth the premium of moving from the Air to the MacBook Pro - well, you should try them out and decide.
Bear in mind that upgrade options on Apple's current laptops are brutally limited.
I.e. there are none. You get what you buy and that's it.
So choose accordingly.
ETA: Things that Apple do really really well on laptops:
* Keyboards - not mega-standout, (my new Dell Latitude work lapper has a keyboard that's on par, albeit not backlit) but they're really nice
* Trackpads - seriously, best trackpads ever
* Screens
* Battery life
Things that they don't do so well:
* Not blowing a planet-sized hole in your bank account
* CPU/GPU performance
* Limited RAM and no upgrade path means futureproofing is limited
* Limited storage and no upgrade path means futureproofing is limited (bear in mind that according to MacRumors, a clean install of Mavericks takes 15-20GB; that's a fair chunk of a base 128GB SSD, which of course won't have a hundred and twenty eight actual gigabytes of space)
* If optical disks matter to you, you need an external drive. Note that if you ever want to boot from an operating system DVD, you almost certainly need the ludicrously expensive Apple SuperDrive (roffle $80 option roffle; I bought a Samsung USB dual-layer DVDRW for £20 last year)