Don't buy on a new high. Give it a day or two and see where it's at then. When It hit 900 last week it quickly plummeted back down soon after.
you could always say the inverse of a statement like that. last week it did indeed hit $900 and plummet down to the high 400's, but 2 weeks 3-4 weeks ago it started at $110 and and has not dipped below $480.