Good card. However, If you have more than 2 lv5 monsters on your field and Umi chances are you have already set SSA as well and you are already in a winning position, so this card is more of an overkill in SSA decks. However it can win games in some situations when you need just one direct attack to win and your opponent may stall you and come back next turn.
Mandy gurl, I hope you won't evolve into something like what Valencia have became today. Please stay sweet, kind, and considerate to other fellow y-g-o fans here. :)