It looks like the biggest uncertainties will be resolved this Friday, July 21st. With far above 80% support for SegWit2x, August 1st should not matter anymore (as BIP 148 will not trigger).
That would mean between now and Thursday should be the best time to buy.
On the other hand, August 1st is passed around everywhere as the "day of doom." Many uninformed people out there. So maybe wait till July 31st to buy? And will there be any risks left after Segwit is activated later this week?
The key question is: How much FUD will be left in the market after Friday...?
If you buy now itself,you could get bitcoin at $2581 since bitcoin price has recovered quickly.If you are planning to buy bitcoins on july 31,if this price trend continues,then you may get it at $3000.Bettter buy now itself.Good luck.