Ultimately one must choose on which course he/she likes the best and perhaps to a lesser extent which city they want to live in. But I think ranking comes in to it a bit. If it's a choice between a prestigious uni like Manchester and City, then I'd go Manchester, unless the City one has a course you absolutely love and you really want to go to London, in which case go to City, but if your neither here nor there with course/city, pick Manchester, it's a no brainer. It's been like 26th in the world for Physics in the past and its very high for business.