Apple gear is not professional
"Quote: 'Apple is actually moving the Mac away from the professional user'
Based on what?"
Based on their offerings? The Mac Pro has laughable expansion capabilities (32GB RAM my ass), and unlike with its older counterparts there aren't even professional graphics boards (Nvidia Quadro, AMD FireGL/FirePro) available. On the other side, that probably isn't really a problem because the Mac OS graphics drivers suck big time. And of course the Mac Pro lacks certification for the majority of relevant professional applications out there. It's a joke.
"I wouldn't use anything else for my business - Apple equipment is good value for money its software isn't 'in-your-face' (you can focus on your job), and the hardware/software combo holds up well under pressure."
Maybe your work isn't really demanding then. As to 'value for money', £1800+ for a single processor machine with consumer graphics is anything but 'value for money', a real workstation like a HP z400 can be had with better config, professional graphics and 3 year onsite warranty (compared to the Mac's laughable 1 year bring-in) for less money. And this is a system where ISV support won't turn their head away in disgust because it isn't supported.
"If you're on a Mac, there are better choices, e.g. VectorWorks, ArchiCAD, and many others." Most of the CAD packages for Mac are lowend or for a limited niche (architects). None of the grownup ones like CATIA, SolidWorks or Pro/E are available for Mac (and most of them are still available for old UNIX workstations from Sun and HP, go figure!), which is very likely because Apple at the end of the day does not have any professional gear (aka Workstations). All Apple offers are very expensive consumer PCs.