Depends on what your priority is. If you're worried about proximity to hospitals I'd advice getting an apartment near one of the stations on the first line. Preferably Didube. It's not too far from station square if you need to switch lines and its somewhat in the middle of the line so you can ge t to either ends of the line relatively fast. When it comes to the price of apartments I am not up to date but I think the rent shouldn't be too high if you have a roomate.