The past has shown that services like this are very spotty, at best. The accounts are overloaded with users (due to being "free") which leads to horrible service in most situations, especially with databases. Curious as to how you counter this.
Either the servers are already overloaded, or it is very rapidly going to be heading that way. No free hosting provider gets enough revenue to keep the servers underloaded through optional premium upgrades; simply not enough people will want to upgrade (even less because you offer "unlimited" everything for free already). But it's not even that - apparently, they make money off of ads on their website. I can tell you right away that that won't work.
Two things. First, the link in the OP has a typo in it. Also, I found it interesting that your premium plan is... in progress?
http://prntscr.com/ete043