Troyman,
I agree on the aio observation you have made, however, it works for some folks and many just like to tweak....so they will tweak no matter what. I have never owned an aio as I went with a sump right from the beginning when I started in the hobby years ago. My 6.6 gallon pico will be plumbed to my basement but not everyone has the luxury of doing this. If I was at a less predictable point in life, living somewhere where I knew I might be moving in a couple years, I'd consider an aio from Chris Delicath w Pico Aquqriums. If someone knew they were moving in less than 12 months but wanted to set up a tank anyway an aio pico would be a good option.