Some of the bugs which are happening will happen across all Skylake and W10 devices to varying degrees, so they're not unique to the SP4. But the SP$ has several common issues including poor microphones, boot failures if the keyboard is attached in certain orientations, screens which don't wake from sleep, Connected Sleep (aka "you can set it down and come back months later with no battery drain) which actually loses between 1 and 10% of the battery charge _per hour_, connectivity problems with some dock hardware, etc. Most of these have work-arounds, or may not matter to some people at all.
The reasons you want a SP4 don't really mesh with what the SP4 is good at, and I would tell you to get a less expensive laptop. Here's why: At the very top of your list for "why you want a SP4" should be
(a) You must have a digitizer/pen interface
(b) You value lightweight and portability above all else
Those are the strong suits of the SP4. If you eliminate those two items, there are several less expensive machines with better battery life, or bigger screens, connectivity options (SD/USB/HDMI/etc).
If you just want it for the shiny, you might be disappointed with the rough-around-the-edges software. If you aren't interested in spending hours online searching for work-arounds and fixes, it's probably not for you (though that may be true of Windows 10 in general, tbh). BUT - if you want the lightest full-pc on the market that has amazing color, great pen interface, and tablet functionality then this will probably serve you well.