I use Maple 16 (I haven't bothered buying any of the newer versions) and it has the Java GUI. The GUI is pretty bad, but if you make sure you work in worksheet mode rather than document mode, you get the old style at least. I also turn off the sidebar. I don't find it to be too bad on my Macs.

I still use Maple mainly because of familiarity. I've been using it since the 90s. I'm a contributor to SymPy, but even then I can think through the problem quicker using Maple.