I currently use a MBA mid 2011, and I think it works ok. Build times are ok for my current project. 1:30 minutes for a complete rebuild, and 15 seconds for rebuild of one changed file. The simulator runs a bit slow, but I think it's ok. My project is based on SpriteKit with a physics engine, so it's quite calculation intensive. Has anyone tried out the m3 version of the 2017 rMB with a similar use case. My MBA battery is running out of cycles, and the power cable is a mess. I guess that the top speed of the rMB is significantly higher than my MBA, but my worry is that I don't know how the rMB handles load peaks. How will it handle that 1.30 (90 seconds) build? Will it build at high speed only for a couple of seconds, and then revert back to 1.2 GHz mode? What about running in the simulator? Will the rMB be at least on par with my MBA, or can it even be slower? I know that an MBP might be a safer choice, but I like the sleek fan less design of the rMB. About lack of ports I think I've read something about a possibility to debug devices through wireless. So maybe that's not a big concern?