One of the issues that has been worrying folks is the prospect of a broader regional middle east war following an Israeli strike on the Iranian nuclear facilities. I think though that given what has been going on in the surrounding countries recently, striking around now would really limit any blowback.
Think about it, following last month's coup in Egypt, the military, which has a history of cooperating with Israel has been actively destroying smuggling tunnels into Gaza and even actively battling with Hamas and other jihadists in the Sinai. Hamas' ability to respond will therefore likely be limited as they simply won't have the supplies to mount any concerted effort.
Hezbollah, Iran's ally/affiliate, has been involved in a costly civil war in Syria and as a guerrilla organization, doesn't have the means to fight a 2 front war. Any major attack on Israel could result in the loss of Syria from the Iranian axis which is clearly something the Iranians don't want. Especially since all they can hope is some symbolic revenge on Israel.
As we've seen the last few years, the middle east is anything but stable and so this current window can close quickly. Israel might be smart to strike while they have a chance to avoid a major conflagration.