The best thing to do is go over to the nex forum and read on the issues. Um not saying its a had phone but it may be a had deal for you. It just depends on what you are trying to get out of a phone. Best of luck!!
The Gnex is a good developers phone so if that is what you are looking for then it's worth the trade up.
But I have 3 friends that have the Gnex and have alot of issues with theirs. Keep in mind they are simple phone users they don't root or flash their phones they just buy them and use them stock so they expect to have a phone that works out of the box and currently they are not happy with their phones.
Now before i get a bunch of angry Gnex users replying to this I'm simply stating what my friends who own STOCK Gnex phones are saying,myself personally If I had the Gnex it would be rooted and flashed probably on a daily basis because that is why I buy smart phones.
I had data connection problems too. I lived right on the fringe area of 4G and my phone would just completely lose it's data connection. On December 15th they turned the 4G on here and WOW, no data connections issues at all.