iZotope Ozone Maximizer has a wide range of choices when it comes to
audio-limiting algorithms, and this gives you plenty of options to settle for a sound you are pleased with. On the other hand, Image-Line's Maximus is somewhat okayish for general audio limiting but I wouldn't classify it as something suitable for contemporary loudness wars.
Image-Line's Maximus might also be less user-friendly for those getting started in music production and sound engineering. So all-in-all iZotope Ozone Maximizer is more beginner-friendly just like Waves Audio L2 Ultramaximizer and FabFilter Software Instruments' Pro-L VST/AU.