Putting aside my novice experience of keeping a reef tank, I've found the tank to be a good starter tank. I've had the Aqua One 190 set up for the past 3 years. It's my first reef tank but had I researched some more I might have bought differently.
It's quite a tall tank and, even though I'm 6ft1, it's a pain to clean and move the aquascape (when needed in the early days). I've found it's also quite noisy when the water flowing from the tank to the sump as there's not much option to angle the down pipe.
I've found also that the upper panels are quite thin and don't really support my lighting requirements which hang on the upper back panels. I had to find a spare wood panel to thicken out for the light bracket to fit.
The sump is not ideal either. At first I didn't give it much thought as it was my first sump. However, there's very little space inside and really the only option is for a hang on back protein skimmer which from what I can find is a limited range for the available space.
All in all, I will look to upgrade at some point in the future and hope to be able to sell this tank.