in my opinion it is best to buy before August 1. There maybe FUD spreading around but if you analyze the situation, the possible answer to the long problem of Bitcoin to scale is about to be fixed with this implementation. I only see positive on this even if the possible chain split will happen. I also believe the majority chain will prevail and maybe lose some of its current value but you still have the minority chain that have also some value and may probably recover the lost value of the majority chain by selling them.