A Macbook running Windows via Bootcamp is horrifyingly terrible. Neither Microsoft or Apple support it (Apple direct you to Microsoft, Microsoft direct you to Apple), it often breaks (if Windows works on Bootcamp you won the version lottery, although running older versions of Windows on newer Boot Camp can help (e.g. if you installed Windows 8.1 when it first got released you're SOL, even Windows 8 wasn't supported by Boot Camp for almost a year after release!)).
Plus the Windows Macbook drivers are simply terrible. They're the iTunes of drivers. Want your battery life cut by 2/3? You got it. Have a model with both an Intel 2D and Nvidia 3D graphics setup that is meant to switch? Not supported in Windows, Nvidia 100% of the time, also causes the Macbook to overheat as the Nvidia 3D graphics run at almost max (which further destroys your battery life!).
I really cannot bad mouth Boot Camp enough. Simply a terrible experience through and through. There's nothing redeeming about it, even Apple's "geniuses" recommend using Parallels Desktop instead(!). When Apple's own people are saying it isn't worth the headaches and hassle, you know it is bad...
OS X is a wonderful OS frankly. You could do much worse than to buy a Macbook, use OS X, and use a few Windows applications rarely via Parallels Desktop. A lot of people do that, it works great. But mark my words, Boot Camp is shit, Apple doesn't care and hasn't cared for years and years, and they don't "really" support it.
Thinkpads (not Ideapads, ick) would be my call for best PC laptop right now. The T540 is a safe choice. But they have a variety of form factors to choose from.
Having an SSD will help as swap can be utilised to make up for any deficiencies you might see with RAM. Although expect slightly longer loading times than you're used to running on bare metal.
Someone1234 seems pretty down on Boot Camp but I have had great results from running Windows 8.1 on a 27" iMac. I honestly can't think of one problem I have had. Of course, it could be much different on a Macbook Pro.
There are only 2 downsides I've discovered: 1. It doesn't support hi resolution on a 2nd monitor. 2. Boot camp doesn't have Ethernet drivers. You have to download them separately. I use WiFi at home and office so I never noticed the absence until the other day.
