sylvia said:
fishdudein - I wouldn't reccomend a common plec for anyone's typical community tank. They grow to 18 inches so are almost as unsuitable as the CAEs. However, there are other plecs that do a good job with algae. My personal prefference is for the bristlenose because it also has such an interesting appearance and they don't grow larger than 5" and don't need driftwood like many other plecos for proper nutrition.
I always recommend otocinclus for the "typical" community tank. I have never had a problem with them, they are peaceful and do a great job grazing on the algae.
If a person has a large (55 gallon or more, preferably more), then "common" plecs are an excellent alternative. The larger fish usually housed in such tanks would necessitate another large fish to be housed with them. Why do you say they are almost as unsuitable as CAEs?
I have a 14" plec that I have kept for at least 10 years now, and he is the most non-aggressive fish you could ask for. CAEs I have kept in the past have been holy terrors, I don't recommend them to anyone. But I have never, ever had a fish die due to harassment from a plec.
edit: I have heard of incidences where plecs have harassed discus, trying to suck the slime coat off of them.