I know that Utilities can use either PSSE or ASPEN for power flow, short circuit analysis, stability. If you have the two softwares, what software would you recommend to use and why?
In our utility, PSSE is used for modelling Transmission lines, generators etc. I'm probably dating myself a bit, but it has the advantage that you can run scripts to look at multiple scenarios and 'let it run'. For example, find the fault level on hundreds of busses with a single run. It also has add-ons that allow substransient modelling, so you can see how each generator handles disturbances and see what happens with voltages and generators. In North America, lots of utilities use it so that all can share system info with each other in a compatible format.
On the Dist side, we use CymeDist, which has analysis features geared for that. Things like where to put a cap bank, arc flash, protection coordination, alternate sources. It works with CymTCC which is geared to Protection coordination.
Also, our utility uses Aspen for Protection Coordinaton on Transmission, though I don't specificlly know what the pluses are since I haven't used it.