Some people don't like new things...they actually have to read the instructions. An Aquia toilet takes a little more time to install than a "normal" one. It is not hard but it is different. The toilet works fine.
One piece toilets have fewer connections to leak, but, they are potentially heavier than a 2-piece (you could put the bowl of a 2-piece in place, then add the tank rather than having to lift the whole thing).
So, if you aren't used to lifting what can be a fairly heavy toilet, then a 2-piece may be easier.
A one-piece has fewer nooks and crannies, so it is easier to keep clean.
If you are a petite woman trying to install a one-piece, you probably would not find it particularly easy, if possible to lift it at all. You might have a chance with a one-piece. Otherwise, pick one you like that has good test results or pay someone to install it.