yes, you're always going to pay an Apple tax.
not according to the Anandtech article -- it's cheaper than comparable PC brands.
the machine is upgradeable with almost all its core components. That was people's main fear, that when purchasing this you'll be forced into buying a new one if you need to upgrade.
that is not the pro's fear. we don't upgrade CPUs -- we retire the workstation and get a new one. dorking with DIY component upgrades is an enthusiast's activity, not an enterprise pro's. the pro's concern is with performance. apple has delivered on that.