That's true, the Marinelands and the Aquaclears are the best HOBs, IME. But if you're thinking you want to stick with Marineland, I would recommend the Emperor 280 over the Penguin 200. First of all, that would give you close to 10x turnover per hour, which IMO
is a good rule of thumb for tanks filtered with HOBs; and second of all, as I understand it the quality of the Emperors is superior to the Penguins. I personally don't like the proprietary cartridges in the Marineland filters (though I really like the Biowheels), but I have to say that after using 4 Emperors I have found them to be exceptionally reliable. I like to stick filter floss in the extra media basket for a little more mechanical filtration and I think they do a great job.
That said, I am also a fan of the Aqua Clears. If noise matters to you, they are definitely more quiet than the Biowheel filters, and they don't make that churning noise when you adjust the water flow. I've used a lot of ACs and haven't had any problems with the water not being pushed through the media. I use them without the carbon insert, and put a second sponge where the carbon normally goes, like richiestang mentioned. Then I put the BioMax on top of the sponges. Aqua Clears are a lot cheaper than Marinelands in the long run because they use the sponges as media instead of cartridges. You can rinse the sponges in tank water every so often when you do pwcs and they last for a really long time.