I've gotta disagree with you. The main reason why the Merkava is so good is because the Israelis knew exactly the kind of environment that that tank would be fighting in. The Abrams is probably one of the best all-around tanks in the world, if not the best.
Both the tanks use similar systems of engagement and optics, but the abrams is are made of light armor which is chemically upgraded, hence light and thick, the abrams' survivability is based on his moving speed and silent engine. the merkava 4 is highly known to be the best survivability tank in the world, also having the engine up front with a rear exit (i think only tank in the world actually using this) I should know I've been to war with it Had tanks in my platoon eat 5 of the russians advanced rockets in the face and the crew didnt even know about it (syria gives hizbolla russian purchased equipment ;/) also theres a large difference in power, the abrams only have 500 horsepower which is like a merkava MKII the MK4 has 1500 horsepower, can shred many sorts of terrain without any problem. Not sure about active missile protection, but the MK4B's are starting to equip themselves with our own active defense system called 'wind coat' which kinda rocks ^_^
Nah, the abrams has 1500; the gas turbine is, IIRC, the same one as used in the chinook. And the abrams is composite armour, like all the NATO MBTs. Chobham, which is apparently layers of various different densities, and still classified.
yea actually recently seen 2 national geographic shows one about the factory of the abrahams and one about the abraham analysis, their new engine seems awesome (same 1500 hp but much more silent and efficient) however, the more i watched it the more i laughed, merkava 4 is so similar its funny, i didnt see anything in it the abrahams had that the merkava doesnt have (except we dont use reactive explosive armor on merkava tanks we used to do it on our old american/brittish type tanks) pretty sure our integrated digital field combat is more advanced though, as its also integrated with the entire army, plus theres a secret system i sadly cannot discuss but its awesome, secret tanks ftw
forgot to mention I was disappointed though they talk a lot about its engine power and terrain mobility, I haven't seen any 'rough' terrain driving of abrahams, mainly flat ground/roads, I'de really love to see how it runs in tough land, im sure any country has rough landscape! though i was a gunner and not a tank driver, my crew rode lots of really rough terrains and rocks/boulders, the tank's 90-100 tons easily turns some of them into dust