Hey.
I don't really know much about Warwick or Exeter but I am a current student at Nottingham.
Firstly, I believe you should choose the uni that appeals to you the most. I don't read rankings because I don't think they show the true aspects of the university, they are focused too often on figures and not really on the actual experience. Though a degree at all three would be looked upon greatly by employers.
Nottingham has invested a lot in its campuses - the new science library is currently being finished and I love how modern and open it is (as a UON student you can go to any of their libraries regardless if it is your home library or not). They are also investing in a new sports centre which should be finished next year and are also upgrading the SU areas, so I feel as if they really value their students. We are also one of the top universities to be targeted by employers
University Park campus is absolutely gorgeous and there are loads of places to explore and inspire you! I also feel a sense of community within our students and also within our courses.
The city is a very safe place - ignore all the stories. Nottingham has a Purple Flag status meaning it is a very safe place at night. The city is a decent size. There are a lot of activities to do within the city and loads of places to eat and have a drink. Really something for everyone. My favourite place is Kitty Cafe.
If you choose to go to Notts, you will end up with a respectable degree and will have the time of your life