There are threads everywhere mentioning it and some good advice on how to deal if you have issues. It all centers around touches not registering how you want sometimes. No it wouldn't stop me from buying another Nexus. It's simply an awesome phone. Root it and it gets even better.
For a quick summary of what you *might* read; The jury is still out if this is user error, software or hardware related. There seems to be several scenarios all related to touchscreen issues. First off, if you have shoddy hardware (dust, bad fit), send it back and keep sending it back until they get you a good one. Whether the actual screen hardware is an issue remains to be seen. My fit and finish is perfect.
2nd, seems like screen sensitivity goes to the edges so look at how you hold the phone and see if a part of your hand is touching the screen. A case helps. Also the 4 hard buttons at the bottom, be sure to touch just above the middle and it responds well.
3rd, if all else fails, root. I did and the improvements to multitouch, bluetooth and general phone performance are well worth the effort.
Don't let the sh!t talkers scare you. It's a great device. I had all 3 iPhone versions. Don't miss them one bit.