I might just add that I have used all three set-ups RTR mentioned, the OERFUG is new to me but in concept and short term application it seems to be fabulous. I ran conventional with air pump many years ago, and switched over to powerheads because of my personal hatred for air pumps. The pwerheads did a better job with the conventional set-ups IMO, not to menton the silence and dependability. I was turned on to RFUG about 12-13 years ago, and ran them with high bio-load Oscar tanks. they are an absolute Godsend with messy fish. The RFUG is IMO one of the best ways to prevent substrate build-up and anaireobic (sp) pockets. I honestly don't use any conventional flow set-up and don't intend to again, but do know that they work well if maintained well. I was ready to scrap the idea of planted tanks because I like the RFUg well enough to use them in every tank. I read a little about planted set-ups, and despite RTR's caution about newbies planting RFUG I did it anyhow. Thus far it is working well, but it has been less time with my tanks than RTR's set-ups, and he is far more experienced with plants. so I'll probably leave the article writing up to him on that one. For any filter there is always pro's and cons, but IMO UGF, RFUG, and OERFUG are all excellent formats if understood and used properly.
dave