I work at a pet store where we have Biorbs as display tanks so I can give you a little first hand experience:
Pros: Biorbs are nifty little tanks, and they definitely have a wonderful design element. Lots of ornament options, and the service kits come with bacterial additives to boost your biological filtration. Very simple, straightforward maintenance, just pop the cartridge in and go. Filter and LED light is built in, and air driven filter ensures excellent aeration.
Cons: The replacement filter cartridges are going to be pricier than most other common ones. They're acrylic tanks, so be wary of scratches. If you're using tap water, the fine spray from the filter bubbles will leave mineral deposits over the lighting, so you will either need to clean it regularly or lower the water level.
They're easiest to maintain when lightly stocked (livebearers like guppies and platys are perfect, or small tetras if heated). In my opinion the filtration is not powerful enough to handle goldfish like it shows on the box.
