Late to this party, but your inclination to look into the XPS series is a wise one if you get into Linux. Ubuntu has really matured and is shaping up to be a fantastic choice for a data sci and development alternative to macOS. Even for a ‘regular’ user, Ubuntu has made some giant leaps compared to other distros thanks to Canonical and others making a push for user-friendliness. Data sci isn’t my gig, but hardware, software, and web engineering is.
The status of Apple hardware is meh. Typically over-priced and out-of-date spec wise. The same money can go towards a very solid Windows/Linux rig. I say that as someone who’s been pretty pro-Apple over my life. The upcoming hardware event (probably November-ish) will be interesting as new MacBook Airs are rumored. This has been a much-desired refresh for many years and these models are what really catapulted macOS hardware as dev environments, but have only seen minor spec bumps over time. The Retina MacBooks are severely under-powered and a single USB-C port is laughable then the jump to something better (MBP) is a massive price premium. Not to mention, data sci tends to be pretty CPU/RAM intensive and upgrades for those on Apple are even more spendy.
If you’re really wanting macOS, wait a couple months to see what comes out. If you’re willing to pickup something new and becoming extremely popular, go with an XPS. Their Linux support is tough to beat for something mainstream. Yes, there are various shops like System76 that specialize in Linux or even Chromebooks (with some hacking around), but, honestly, Canonical/Ubuntu is putting time and money into Dell support. You’ll also have no issues dual-booting with Windows which is nice depending on where you end up. Some data sci people work in Windows as well. If you end up at a macOS site, they’ll have no probably handing you a company computer. Save some money now.