Ok-
1. Wedge pipe- I don't like the wedge pipe, they are hard to get "just right"
2. The pump- I have seen quite a few of these in action, and within a few months, many had pump issues.
3. Required water level- they MUST be in atleast 8-10 inches of water, other wise the pump isn't strong enough to properly function the skimmer
4. Collection cup removal- very difficult, can often result in flinging skimmate all over the inside of your stand
5. The cone models- the acrylic is not extruded. It is wrapped and sealed... Well supposed to be sealed, I've seen 2 split at the seams
Edit: I'd probably compare it to a seaclone. Coralife skimmers are a step up from eshopps, IMO.