A word of advice to everyone visiting Penang Hill: don't be foolish and try to buy tickets on-site!
I learned this the hard way. There are no express tickets available on-site; the Penang Hill express lane requires advance online booking.
The queue for the regular cable car was so long I almost got heatstroke, and then it started raining!
Even worse, nobody reminded me that I needed to collect a separate ticket for the downhill section! Queuing for ticket checks wasted an extra half hour.
Scenery: Nice
Fun: The queues were too long