I ended up "jumping ship" (still use an iphone and an apple watch) from a 15" macbook pro late-2013 to an Alienware m15 (R1, not the new R2 model they also sell now). I don't mind windows and used both interchangably on the mac.
It has the following major hardware differences over the MBP 15:
the good:
1. a very comfortable and reliable keyboard with a numberpad
2. an nvidia 2070 max q, for much better GPU performance than any macbook pro
3. a second user-upgradable M.2 slot for another SSD (i put in a 2 TB intel 660p for under $200, giving me more storage than any MBP)
4. user upgradable ram and much cheaper ram options
5. 4k IPS screen
6. 1080p webcam with dual mics
7. Better port selection, it includes Thunderbolt 3, but it also has 3 full size USB, a displayport, and an HDMI.
8. 90 watt/hr battery
9. good build quality, and screen goes back almost 180 degrees
10. Price is incredible compared to mac. I paid about $2500 for the following specs:
intel i7-8750H
nvidia 2070 max-q
32 GB ram
512 SSD boot drive + added 2 TB intel 660p storage drive (2.5 TB total storage)
90 watt/hr battery
4k IPS screen
Windows 10 Pro
the bad:
1. heavier and thicker than a macbook pro due to the 2070 max q (15 macbook pro late-2013 = 4.5 lbs, alienware m15 = 4.8 lbs)
2. trackpad is about as good as the ones in 2010 macbook pros, but worse than the more recent ones. Good enough, but not on parity to newer macs.
3. no dynamic brightness adjustments on the screen like the MBP, you have to adjust it manually depending on the room you are in
4. speakers are just ok, and not as good as on the MBP
5. power brick is huge compared to mac, but necessary due to 2070 max q
6. not quite as easy to set up as a mac. I'm using throttlestop to throttle and undervolt the CPU to keep temps reasonable under heavy workload and using the alienware built-in fan software with a custom fan curve. After the tweaks, i lost about 5% CPU performance at load, but my CPU temps don't go over 80C. Kind of a pain to set up and find the right balance for your CPU, but once it's done and in start-up you don't have to touch it again.
Overall, i'm pretty happy with the new laptop. I still use the MBP with a couple external hard drives attached as a home server.