well i think you should stay with a cheaper pair untill you get better, cause powerisers are like $700 aud and skyrunners are $300, like with me im staying with skyrunners untill i get good at flips and that.
but i would go for 7's over powerisers, might cost a little bit more to get over to aus but i hear they run rings around powerisers.
just my 2 cents though.