As a very general rule for Limited, I would look to play something like this: 1 mana: 02 creatures 2 mana: 46 creatures 3 mana: 35 creatures 4 mana: 4 creatures 5 mana: 3 creatures 6+ mana: 12 creatures That's far from hard and fast, but it's a good place to start
Its ability to turn lands into useful spells in an ongoing way is difficult to disrupt and really hard to beat for any slower deck, even a deck that simply requires a certain mass of hand size to go off
The thing that makes this card slightly more annoying and therefore slightly less played is not that you don't kill the thing you bounce but that so many cube cards have enter the battlefield effects you don't really want to give them again
Rofellos provides level of mana acceleration in the Command Zone is simply too good
Ive found that this card plays well in Rule of Law strategies that have a high number of creatures, as you wont mind taking a turn off from casting a single spell to level this up
If the spell you cast has in its mana cost, you must choose 0 as the value of X