You could demo Cubase Elements, for that you don't need a dongle. It doesn't have all the bells and whistles of the Pro and Artist versions, but it gives you a good insight into how to work with Cubase.
Apart from that I don't find Cubase clunky. You have a lot of choices how to go about things, in that way it reminds me a bit of FL Studio and that's one of the things I really like about Cubase. I work a lot with shortcuts and macros and for that kind of workflow Cubase is ideal. I'm on PC and for me Cubase runs smoothly without any problems, so I don't know if it works ok on Mac.