Macbook Pro laptops don't have 4K monitors but it can do 1440p, already a nice step up from 1080p. When uploading my 4K files to YouTube in addition to 4K playback option folks with retina displays can now enjoy it in 1440p as oppose to 1080p.
Sampling down 4K to 1080p is better than recording in 1080p.
My 4K mp4 files is about 5GB for every 10min, just drop 3TB time capsule or WD on your network and you won't have any storage problems.
Here's first 4K video I did and I noticed significant bump in quality of video files.
If you can afford it, don't settle for 1080p. 4K displays will be as common as 1080p displays in the next couple years.
What software do you guys use for scaling the footage down from 4k to 1080p?