I have Ozone 3 and like using it. I basically use it for its limiter, which I really like. I like the way everything is laid out and in one plug. I use mine in Wavelab after I mixed my songs down to 2-track.
I don't use everything in the plug, like Harmonic Exciter or MBC. I'll use the EQ when I'm doing more than one song or if I hear something stand out when I play it the car, laptop, etc.
I heard the dither feature is very good, but I wouldn't know about it, never hear any difference with ot without. Probably it has to do with the type of music I'm using it with.
A lot of people will be negative towards Ozone because it is easy to misuse or abuse. People will just pull up a preset and expect it to magically make their songs sound good. It doesn't work that way, but Izotope is marketing to that mentality. Start with a clean slate and make only the adjustments you need to obtain your goals. And experiment... you'll learn a lot about your mixes when you try different things.
peace,