You can find the resolution online. It depends on whether it's a 13" or 15" model. It is less than 4k, but has a higher DPI then 4k desktop screens. The only thing which gets as sharp are the 5k 27" screens - that's likely why Apple decided to make them.
Whether a monitor looks really crisp depends on a combination of number of pixels, screen size and viewing distance. For 4K monitors the typical size is 27" to get the "retina" quality at normal desk viewing distance.
