I honestly wanted to like Tranzit, but I just don't have the patience. I know they tried to ease the pain by adding the lampposts and allowing you to run through the fog, but I still can't deal with all of the travel time. Just getting all the perks, setting up the pack-a-punch and chasing the box around can take over an hour. I understand why people enjoy the freedom/exploration of Tranzit, but I have never been into exploring the nooks of every map or doing easter eggs that require hours of time potentially wasted when you don't get the box item you need (or do things out of order). I find Tranzit essential unplayable.
Survival mode is fine although should be better. They should have allowed for more customization with which perks to add to the map and whether or not to include pack-a-punch or box. Even allowing to specifically chose which weapons to allow would have been nice. Instead, they set up each area for you and allow for very limited customization. Very disappointing. The areas themselves are limited and exactly as they appear in Tranzit. The nice thing about them is that they are compact and, therefore, very action packed. But their size also means that they get old quickly.
I actually really like Grief. It does suffer from frequent lag/framerate issues. However, the competitive nature is a great new take on zombies. I have played more Grief than any other mode. My only complaint is that the maps were not specifically designed for Grief and it shows. Strategy is limited by map layout and both maps encourage cheap strategies. I would love to see them put out a map specifically for Grief.
Overall, I would give zombies a 7/10. I am really looking to see what they do in DLC.