a rhemora and a prizm pro both run around the same price, are both black, and are both rather sleek looking as far as protein skimmers go. they are both hang on applications, which means you do not need to invest in a sump, and if you really needed to remove it, (say you had a visitor over or something and wanted to tidy up a bit) you could, though skimmers work best once they have been set up and running for a while.
I am not sure if the rhemora has a surface skimmer option, maybe someone has come up with a diy for one, but i know the prizm pro has this as an option.
in my opinion, if you want to keep some of the larger, more delicate species, you will want to invest in a sump and skimmer, or a wet/dry and skimmer. this will allow you to place the skimmer, the heater, and any other things like a thermometer underneath the tank, and not in the display tank its self. This also gives the added benefit of adding gallonage to the system, increasing the durability of the system.
if you want more information about going this route, just doa search either here or in the new hobbiest section for sump, you will find tons and tons of discussions about them.
i only bring this up now, because if you choose to go this route you are looking at 300 dollars or so for a prebuild wet/dry, maybe 200 or so for a setup if you make it yourself. with a hang on skimmer of good quality running about 200-225 dollars, you could in theory make a nice sump for less, or at least not have to buy twice.
hope that helps.
