Ok I *ACTUALLY* have a biOrb30 (8 Gal) and it is a fantastic tank. Here's what I would say about it:
- Regular maintenance like water changes are VERY easy. The technology that the system boasts (and it is not a lie) helps so much with creating a very easily cycled tank. Since I've got my goldfish in there, I know it's overstocked so therefore I check my tankwater EVERYDAY and all the numbers are what the should be. The numbers HARDLY move at all because the tank has both a circular physical filtration from the bubble tube and the UGF, and the ceramic media has vesicles in it to provide 5 star housing for beneficial bacteria. If you just happen to be super busy on a water-change day, you could skip it without a sweat and do it the next day.
- The tank itself, is eye catching. I've gotten loads of compliments on how awesome my biOrb looks. As for decorations, eBay has loads of cool decorations you can put to hide the bubble tube or to make the bubble tube a volcano or other things that suit your fancy.
- Distortion Effects: I can see this may be a problem if you like to put a lot of decorations in your tank. I've seen a couple Marine biOrbs with just a centerpiece-coral around the bubble tube with some clown fish and you can see them fine. However I would think that a LOT of decorations can cause smaller fish to disappear (especially ones that like hiding). However it is kind of cool when they reach a reflection angle and look HUGE. I've seen youtube videos of Bettas in them, and I can see them just fine. It's just stuff like tetras and danios that disappear intermittently, haha.
- Long-term Maintenance (filters/airstones): This is NOT difficult to change, no offense to the people on here who said it's difficult to change, but you honestly need motor difficulties not to be able to do it. The bubble tube is connected to the filter cartridge, so all you need to do is twist it C-Clockwise (or clockwise on some of their models) and it pops out. Twist it again to remove the bubble tube from the cartridge. Reverse directions to put it back. A CHILD CAN DO IT. The airstone at the bottom just pops on and off, not too complicated there.
When you purchase a maintenance kit, you get: Filter cartridge, StressZyme, StressCoat, and a soft pad to wipe the sides of the tank, all for a price of $9 CAD. The Zyme an Coat come in easy packages where it is pre-measured so you toss the whole package in during your water change. All this also comes with clear instructions.
The soft pad is pretty nice, it comes with two sides, just like kitchen sponges. It's got a soft side to just clean the inside of the tank, and the slightly rougher side for those stubborn pieces of muck and/or algae.
- Betta-specific stuff:
For the "labyrinth space", I would say there is an adequate amount of space. The instructions say you're supposed to only fill up the water 2" above the top of the bubble tube. I definitely won't say it is IDEAL (especially if you're looking at the 4Gal), but I don't think it would be a big problem. The default Halogen light you get MIGHT cause some obstruction but that is a personal thing. The flatter LED light is obscenely expensive, and I only got it because the Halogen heats up the water like no tomorrow and my goldfish like cold water.
The ceramic media is a little rough, so it might be a good idea to purchase large, flat stones (they call theirs FengShui stones lol) to cover the ceramic media to protect your betta. Since these stones are big and heavy (for the fish, not you) your betta wouldn't be able to push them around, so no fear of suddenly exposing the rough media.
I have heard some people complain about the strong current, and I know my biOrb has a fairly strong current as well (that's how the filter works), but there are people who put a clothes pin on the airpump tube to soften the bubbles (and subsequently the current)
- Price: To me this is the real clincher for this system. I personally wouldn't pay that much money for ANY of their systems for one fish. I think these tanks are best suited for housing a small-medium sized tropical fish school such as 10 cardinal tetras or something. I mean, I do love my bettas, and I do like to spoil them...but not this. It's a little too extravagant. I'd rather spend that money getting a 20 long and housing 4 males or a sorority.
That's just my two cents. It's a fabulous system, but I definitely prefer the biOrb Life systems, the square/rectangle ones, with no distortion. But they are more tall than wide so the surface area isn't great for Bettas.