As far as I know, NUST is best, then comes GIKI (boring as hell place), then UET, then Mehran (friends told me that studies there are predominantly in Sindhi :s and I don't know Sindhi), then NED. This is for Engineering. If you add business/computers, then Comsats, LUMS also come into the equation and I would place LUMS at first then, and Comsats just above NED. When medical comes into equation, then Aga Khan would be above NED.