As far as a desktop Mac, a suitably configured iMac is more than powerful enough for development. A $2100 5K iMac - 6 Core I5 3Ghz (turbo boost to 4Ghz), 256GB SSD, 16GB of RAM. The RAM is user upgradable and an external SSD drive would be as fast as any normal internal SSD drive.
As far as a laptop? I'm not spending my own money on a development class laptop. I hate developing with just a laptop. I have a dual external monitor setup at home and at work. My next personal computer will definitely be a desktop. You still get more power and more thermal headroom on desktops than more expensive laptops.
As far as a laptop? I'm not spending my own money on a development class laptop. I hate developing with just a laptop. I have a dual external monitor setup at home and at work. My next personal computer will definitely be a desktop. You still get more power and more thermal headroom on desktops than more expensive laptops.