My girlfriend has the red TPU case and I have the green Naztech Vertex. Both are great cases, but I prefer the Naztech.
The TPU is not quite a soft case and not quite a hard case. It is just flexible enough to put the phone it. The only issue my girlfriend had with the case is that the camera, volume, and lock buttons are covered and can be difficult to press. She ended up cutting out small sections for the buttons and it has helped.
I like the mixture of the hard and soft cases for the Naztech. At first, It can be a little difficult to correctly line up all of the parts of the soft case. After taking off and putting on the case a few times, I have figured out a good technique to get the case on. My only complaint is that the soft portion can stick a little to the inside of my pocket when trying to take it out.
I think either case would be a great choice.