I bought one for my girlfriend for her birthday.
I set it up as a lazy planted tank...
For the substrate I used Seachem Flourite Red.
That, and 8 hours of the light that comes with it seems to keep the plants healthy and happy.
Growth is steady.
Even the hair grass has started to send out some runners...
The only issue I had with the tank was the flow rate of the filter pump. It was much too strong, but that is easily changed by twisting the nob thing on the pump.