I liked Sheffield so much that I never left after Uni. Upsides include the Peak District on your doorstep, a compact and easy to get around city (at least on the West/South side of the city where most of the students live), and the FACT
that it's the real ale capital of the world.
Downsides aired by students tend to be along the lines of it's a bit lacking in nightclub action (at lease since the demise of Gatecrasher
) and fancy shops (not that this ever bothered me).
Rent-wise, there's been an explosion in the number of self-catering flats for students (albeit at the expense of University-owned halls), and I suspect that there may have been a knock-on effect in the buy-to-let sector.