I just went through this exercise myself. I love Apple products, but there are some limitations and I am not a huge fan of the current trend of their products not being user serviceable (ram, HDDs, etc.). In any event, for the money, I decided a non-Apple laptop was the right move for me.
The first thing you'll see is that most Windows laptops are built to meet a certain pricepoint and thus have very sh*tty TN panels which are useless for any photo editing. Be prepared to easily spend over $1000. Will this be your only workstation (i.e. no desktop?)? If so, you'll need to get one with the best display you can afford.
I went through various options that included Dell, Lenovo, HP, Asus, and Sony. All have options with an IPS panel.
-Dell - The Dell with the IPS panel is the Precision business line - they are workhorse laptops that will easily eclipse $2K and be quite heavy. Dell also has some high gamut TN panels, but they are glossy, so I nixed that idea.
-Lenovo - The x230 has a decent IPS panel, but it is a little lower gamut than most would like, but still better than most TN panels. The T530/W530 have a high gamut, matte TN panel that is highly regarded.
-Asus - Zenbook Prime has an IPS display, but is limited to a paltry 4GB ram which was the deciding factor for me.
-Sony - The new 'S' line has an IPS display as well and looks quite promising, but the battery life did not meet my needs (~4hrs).
In the end, I chose the Lenovo T530 (i5 build with 1080p high gamut TN panel). I will be swapping the drives myself and using a SSD for OS and Apps and a larger drive for storage, as well as upgrading to 8 or 16GB of ram.