Used rfing and ffing, it's not "teh ebil" really. Especially the newer models, since they actually have decent harness height ffing. The main problems with the AOE have always been:
1: difficult install. You are supposed to recline the seat rfing to the level line in all cases, but it takes up a huge amount of room if you do and that often leaves techs in an awkward position trying to explain that the seat can't be used as instructed if the whole family wants to get home today, but that in general, more upright installs are considered safe by people other than Dorel. The base on the seat is wider than the LATCH anchors, making for a tricky LATCH install, and the belt path is very narrow, so using the seatbelt isn't a walk in the park either. When using a switchable retractor for a rfing install, the seat has a tendency to get pulled up easily by the shoulder belt and tip to an extreme degree, forcing you to use a locking clip. There isn't really a lot of space ot fit a locking clip and the latchplate between the base and the shell, so this, combined with the small beltpath leads to lots of hand abrasions and abrasive language. You used to be able to take the base off, but the new models don't allow that.
2: Lack of fit. The lowest harness slots are so low that most babies won't fit the harness until around 6 months old. The highest slots on the 40# models are so low that many kids will outgrow the seat ffing at about 2. Add to this, the highest slot for the headrest is only for booster use, BUT there isn't a lot of clear and visible warning about this.
3: Easy misuse. Booster mode is almost impossible to use correctly. I've seen a few (maybe 5 in 12 or so years) kids actually have a passable fit in booster mode, despite checking hundreds of the darn things. Threading the harness you have to go under the plastic bar but over the metal bar or the adjustment mechanism doesn't work at all. If you pull one adjuster tab all the way open but not the other when you go to move the harness up, you can detach the headrest adjuster thingies completely and they are decidedly NOT easy to put back on.
4: Truth in advertising. Self explanatory.