I think the 2015 model has now replaced the older 2012 model (last that had upgradable parts) as the MBP that power users go for, even though it's almost $2k for hardware that'd be $800 on a typical windows machine.
I already had a TB2 hub and other TB2 peripherals and extra MagSafe 2 power supplies, so no additional investment in adapters, etc.
The kicker was the unit I bought has been purchased less than a year before I got it, so it was still eligible for AppleCare (you can check this w/ the serial number that most reputable eBay vendors provide). The time has probably passed for this, although you could still get a unit where someone else has already gotten it.
All in was US$ 2,050 including AppleCare
Bought a cheap usb c enclosure off Amazon for backups too (swapping the hd) and I love it when I buy a new device that has usb c because I only need the cable that comes with my MacBook for camera and wireless headphones charging. So actually I’m nearly dongle free at this point. Still think it’s a real shame they didn’t keep the inbuilt SD card reader.