Some insight
I've been reading this topic and the statements made about allmost all the different tanks on this globe with great interest. Some of the statements are actually quite interesting and eye-openers, others much less. Of course, there are differences between all tanks. Each tank is developed by and for a specific country/ area. A tank that performs excellent in the desert (Merkava series for example) could prove to perform much less in other areas. The European/ American tanks needed adjustments for the desert, even though they perform well in Europe.
Something I've missed with most comments is the insight on the development of Russian tanks. You can read about that in an article from armor magazine (july-august 1998) entitled "Why 3 Tanks?", www,docstoc,com/docs/69749222/Why-Three-Tanks]Why Three Tanks
For those of you who haven't got the time (or simply don't want) to read the entire article, it comes down to this. The fact that the Russians produced (and thus fielded) three different tanks at the same time to what appeared to be the same requirements had very little to do with different tank threats, but much more with the power of the "Oboronka" (Russian slang for Military Industrial Complex) and the fact that there where two main design bureaus (Nizhny Tagil and Omsk) who where very desperately trying to beat eachother. This goes back to well before WW2 and led to a series of parallel designs with each newer tank designed by the other design bureau.
In short, the KV-1 was built by the Design bureau in Omsk (then located in Leningrad) when Nizhny Tagil developed the T-34/76. This resulted in the development of the KV-2, which in turn resulted in the T-34/85. This led to the development of the IS-2 and IS-3 in Omsk, which then led to the development of the T-54/55 in Nizhny Tagil and so on. Eventually Nizhny Tagil developed the T-72, Omsk developed the T-64 and T-80.
According to the forementioned article the T-64 was a very problematic tank which never lived up to it's expectations (therefore the small production numbers), the T-80 wasn't much better and the faulty autoloader (which was inherited from the T-64) in combination with high fuel comsumption (due to the gasturbine) resulted in the poor performance of the T-80's in Chechnya. The T-72, although the export models proved to be weak, seems to be the only tank in Russian service that fills all requirements set by the Russian DoD.
After gulfwar 2 the T-72BM was hastily renamed to T-90 to try and shake off the stigma from Iraq.
For those who say that the T-72's/ T-90's essentially still use the same gun today as they did when the T-72 was first fielded, you might be in for a nasty surprise. The tanks, including their guns and ammunitions, where steadily improved. The first T-72's where fielded to counter the M-60, Chieftain and Leopard-1 and weren't able to launch ATGM's from their gun tubes . Later versions where improved to counter the threat of that moment and did have ATGM launching capabilities.
The T-72BM (or T-90) was equipped to counter the M1A1, Challenger-2, Leopard 2A4 and ZTZ-96. The T-90A counters the M1A2, Challenger-2, Leopard 2A5 and ZTZ-98. As of september this year their will be an improved version of the T-90A, the T-90AM. Specifics aren't yet known, but it is likely to be meant to counter the M1A2 SEP, Leopard 2A6 and ZTZ-99.
According to some sources the Russians have had DU ammunitions (BM-32) for their 125mm guns since 1978, but haven't used it in combat because it proved less powerful then their Tungsten BM-42. Also, the latest version (the BM-42M) is reported to have the same penetrating abilities as the German DM-53 (as used with the Leopard 2A6).
The Russians tend to equip export countries (including former WP-countries) with inferiour copies from their own tanks. For example, a big difference between the Iraqi T-72's and the Russian ones is that the Iraqi T-72 had an older gun which wasn't able to launch ATGM's from the gun tube and had obsolete ammunition (meant to counter the M-60 and with a much shorter effective range). They had cast steel armor (Russian T-72's have layered composite armor) which was also thinner then the Russian package. Last but not least, the Iraqi T-72's weren't equipped with NV equipment whereas Russian ones have always been equipped with some form of NV.
Then there is the fact of differences in strategical and doctrinal thinking. The west likes to use state-of-the-art technology in combination with well trained personnel, which comes down to expensive vehicles with well trained and educated crewmen. Those vehicles and crewmen are hard to replace, so much effort is put in vehicle and crew survivability.
Russia wants to have their equipment modern, but not so modern that a lengthy training is needed before one can operate these tanks. Russia still uses the lessons learned from WW2, they want vast numbers in times of large scale warfare.
They want to have military equipment which is modern and potent, but also easy and fast to produce, relatively cheap and simple and robust enough that ill-trained people can operate them with good results.
That means that Russian equipment (at least tankwise) will probably never best western equipment in one-on-one engagements, the Russians have always relied on numerical superiority (both in force and production numbers) and the combination of manoeuvre assets with vast fire-support. This means that in case of a war between NATO and Russia (god forbid it happens) for example one Leopard-2A6 would be faced by at least 3 T-90's. The big difference Russia being able to replace rapidly and easily whereas NATO will have a much harder time doing the same. Which means that NATO needs a quick and decisive war, whereas Russia will try to fight a war of attrition. Quite identical to the German experience on the Eastern Front, the T-34's just kept on coming.