I have a different opinion than Scott on buying a MacBook Pro at this time. Yes, a new model - with only a CPU upgrade rumored - is expected by the end of the year, but the 2018 crop is fine - particularly via the Apple Refurbished store, where you save about 15% (USD 2,800 MBP priced at USD 2,380 for a 6 core i7 with 16 GB RAM, 512 GB SSD and Radeon Pro 560X).
I just finished benchmarking a comparably powered Alienware M17 - which granted is a 17" screen and has a full numeric keypad. It's price is 10% less but it gets really hot and the fans are loud in the plastic case even just browsing the web - vs Apple cooling design in the aluminum shell of a MacBook Pro which dampens the sound some. Not that it matters for ARCHICAD, but sound from the Alienware M17 was tinny with buzzing from the plastic case sympathetic vibrations.
The Apple US refurbished 'store' for 2018 15" MacBook Pros is here... but what's available changes daily:
https://www.apple.com/shop/refurbished/ ... acbook-pro
If you don't use other Apple products (phone, tablet, watch etc) so that you've 'bought into' the iCloud ecosystem to synchronize your data across devices... then you might be happier staying with a Windows 10 mobile computer like the Alienware M17. (Note: "laptop" is not the best word for these 'mobile' machines as they run too hot to put on your lap or in bed... and the Alienware, for example, has huge vent holes on the bottom that shouldn't get blocked.)