You get what you pay for. :)
I use my 2+ year old Macbook as a DAW. Runs professional multi-tracking studio software flawlessly. It cost more 2+ years ago than a Windows laptop for sure. But the performance and reliability has been worth every penny. I will never own a PC-windows device ever again as long as Apple quality and reliability remain as they are.
YMMV
Yep, if you absolutely need the absolute best, then Apple's are quite well built! But considering you can get 96% of the quality (8.8 versus 9.2) from a machine costing 25% as much, it's a BIG cost to get that last 4%.
YMMV
Yep. For me, I absolutely need schematic capture, magnetics FEA, and 3D CAD. There aren't any decent (or even ANY) solutions for the Macs, so I'm on Windows. My 4 year old Dell D505 is still chugging along, even though it's flown with me for close to 1 million miles! Only thing changed was a new keyboard (Thomas Kemper root beer and keyboards don't mix) and a bigger hard disk (when I got it, 80 GB was huge; now my 320 GB is getting cramped).