It depends what course you will be doing there. I would compare the course content to see which one you like best.
Not sure about the reputation, as I only applied to one of them. I know some people on TSR applied to both Sheffield Hallam and Lincoln, so you could ask them for more details and opinions. I remember one TSR member chose Sheffield Hallam over Lincoln. However, don't let that put you off, as people have different opinions (e.g. some people might think Lincoln is better than Sheffield Hallam and vice versa). Maybe that person thought that the course at Sheffield Hallam is better than Lincoln (I think she applied for some media type course). It's important to choose a university you like.
As for nightlife, I think Sheffield would be better, as it's a bigger place than Lincoln. In addition, I also heard Lincoln's nightlife is decent/not that bad.
Lincoln has a modern main campus and facilities, espeically the computers. In addition, they are having an expansion on the Media, Computing, and Humanities building. I think Sheffield Hallam has a modern campus too when I looked at their prospectus. In my opinion, Lincoln has the most modern facilities compared to Sheffield Hallam (again it's my opinion).