Ozone 5 is great for both entry-level and advanced mastering.
If you don't know what you're doing and you're just mindlessly applying presets
(without having an understanding of what's going on behind the scenes),
you're going to get fairly mediocre-to-poor results.
By contrast, the presets are great if you understand what they're doing and
you use them as time-saving features.
From there, just like with every other music production tool,
your results will correlate with your skill and experience with the tool.
I like the overall iZotope worflow -- I use a lot of Ozone and Alloy.
In fact,
I just recently bought the upgrade to Ozone Advanced recently after sitting on the
fence for about a year over whether it was worth the money.
The Standard version is good enough to make you wonder
whether the Advanced version justifies the extra price.
If you do end up picking it up, I suggest investing the time and money
in the Groove3 video series covering Ozone. You'll get a lot of bang out
of your buck by learning how each module works from the bottom-up.
-Ki
Salem Beats