the one at bon accord baths-it's small but usually isn't busy,unless you go early evening but it's good for a quick workout between lectures/at lunchtime and stuff plus it's only a mere 1:90 for a student gym and swim and for that you get use of the facilities for as long as you want,there's no time limit on it. the JJB gym's good but for the student membership,nice facilities but he hours you get to use it for are crap especially if you work in the evenings and weekends