Hi Sunny.... Welcome to AA!
I don't have a BioCube but I do have a JBJ Nano Cube 12g, which is very similar (as far as I can tell) with the integrated filter in the back and PC lighting in the hood. That was my first tank getting back in to the hobby a few years ago. I was also attracted to the sleek and stylish design in an "all in one package." Given that I had limited space living in an apartment, I wanted a small tank with big tank features... hence my acquisition of a Nano Cube.
One problem I didn't think about when I first got it was that these tanks are REALLY meant for SW reef setups. So I had to swap out some things in order for it to be suitable for a planted FW aquarium (for details, check out my 12g:
http://www.aquariumadvice.com/forum...-its-all-grown-up-now-227698.html#post2143992).
Basically, the stock actinic 50/50 PC bulbs aren't suitable for FW (you'll get a ton of algae...trust me, I tried it). I swapped those out for a 10,000K and 6,500K bulb. Secondly, the stock pump had way too high of a GPH flow rate that was not adjustable (not sure if it's adjustable on the biocubes). My poor fish were constantly fighting a hurricane of a current...LOL So, I swapped that out for a Marineland mini jet 404 which made the world of difference.
Moreover, the PC bulbs are pretty powerful (meant for corals).. so you'll have A LOT of lighting over a small space... without the addition of co2 or a way to decrease the lighting, you'll get a lot of algae. The high lighting is doable, but you'll need to inject co2 and get some moderate to high light plants that are fast-growers in order to utilize all that lighting and suck up the nutrients in the water so that they would out-compete algae.
With those mods, and the addition of DIY CO2 and Floramax substrate... My Nano Cube has come together pretty well to my liking for a planted tank....
Here's a youtube vid of my NanoCube... I have a listing of all the plants that I used on the youtube page.
Nano Cube 12g FW Planted Update 2012 - YouTube
And some pics
And Jungle Status in all its glory!!! haha