As Jock said Tel Aviv is like any modern mediterranean city. Nightlife is great, the Women are gorgeous but all carry M4's! Jerusalem on the other hand is like another world, it's like stepping back 1000 years in time. We went to Masada which was amazing. Stopped briefly in Jericho, and that place is wired, random bouts of gunfire, and explosions. Tanks and troops everywhere and big massive concrete walls that made the Berlin Wall look like a dry-stone wall.
Oh and as Jock says security at Ben Gurion (on the way out of the country) is off it's head!