actually they have wiped out entire countries military forces before, Syria in the early 70's is one, we have only , barely, with help, wiped out germany ,japan and italy, and then in Iraq we just killed there military force which was a bunch of old T-72 tanks and some BMP 2's, both of which our bradley could and have killed before, so our infantry fighting can kill their MBT's , yet isreal's tanks have to stand up to countries who tank older tanks for no money at all and then they upgrade them with modern everything, including armor, and make much better tanks then they used to be, so all of the countries neighboring isreal have newer designs for older tanks that make them much for effective, like the M50 Super Sherman, and ontop of that, the Merkava can withstand a salvo of about 7 RPG rockets, our abrams can't, the leopard , i haven't heard naything, but the Merkava can also carry infantry into battle which makes it a very viable, ad powerful tank, especialy with it's modular armor, and with all the small wars that go on, they do use more of there tanks then we do ours, they just use them over time, basicly they keep all their experiance and get more, the US get's into a war every other 10 or so years, which is way to long if you want experiance, plus the t-80's can damage the abrams, not kill it mind you, but at least make our crews evac from the vehicle, the merkava, hasn't had a single tank kill one, the only ones that i heard of that were killed were form mines and mas AT infantry rocket fire, if the US made a tank like the merkava, then we would have the badest tank on the market, but with the way isreal is always getting fought with, they know what a tank needs, and speed isn't always a top factor, but it is one of the three big factors for tanks