Best answer: Most people would be better off with the 1080p display rather than spend more on 4K. However, if you're looking for touch or digital pen support with your screen, you're going to want to go with the Dell XPS 13 2-in-1.
4K is overkill for most
The Dell XPS 13 is one of the best Windows laptops available today, and it's easy to want the highest specs and the most features. But the truth is that for most people, luxuries like a 4K display are unnecessary expenses.
If you're involved in creative work such as video editing, then a 4K display is probably a good choice. However, at 13.3 inches, it's not as though the Full HD display looks bad.
The 4K display not only affects price, but with more pixels to push, it affects battery life, too. It's also only available with touch, which means you're getting a glossy finish, something many simply won't want.
The best value option for most XPS 13 buyers is the Full HD non-touch display. With the latest model, Dell currently doesn't offer a Full HD touch version as standard; you'll need to add it as an option, which on a laptop like this isn't worth it.
Most configurations available without 4K
If you want the best performance from your XPS 13, you're not limited to the highest-spec configurations. You're also not forced to get a 4K display that you don't want or need.
The Full HD versions of the XPS 13 can be customized with better specs like an Intel Core i7 processor, 16GB of RAM, and more PCIe solid-state drive (SSD) storage.
The 4K display is offered as an option on the XPS 13, and you can add it to even the base model if you wish for a premium. Unless you're in the market for editing photos a lot or handling high-resolution video, that's a lot of money to spend on something you won't get a ton of benefit from.
A better choice for touch
If you want a touchscreen version of the XPS 13, there is a better option. The XPS 13 2-in-1 is a convertible version with a display that folds right round. It can be used either as a traditional laptop, a tablet, or somewhere in between.
The hardware inside is very similar, too. It starts at a little less than the regular XPS 13 and is one of the best all-around laptops on the market today. Dell has an incredible lineup with its two XPS 13 laptops.
The beauty of the XPS 13 2-in-1 is that it supports Dell's Active Pen, so you can write and draw away to your heart's content. It's an extra spend, but well worth it, and the 2-in-1 variant is the better touchscreen choice for anyone who really, truly wants to have touch on their laptop thanks to the flexibility to use it to its full potential.
Best choice
New Dell XPS 13 (9310)
Save some cash and avoid the touch
The XPS 13 is significantly cheaper without a 4K display, and most people won't really need that resolution. The better choice is to go for the Full HD without touch for the best value.
For touch users
XPS 13 2-in-1
An XPS 13 you can scribble on
The XPS 13 2-in-1 is a more useful application of touch with its fold-around display and support for Dell's digital pen.