1. The tiger was frankly a stupid tank. It's design was the obselete, slope sided inefficient armor. It was too large and heavy for it's own suspension, so it continually broke down and guzzled fuel the germans didn't have. It had a fairly powerful gun, and relatively heavy army, but it was slow, unreliable, gas guzzling, and took up resources that ought to have been used elsewhere, remember for every tank you make of one type, you can't use the money elsewhere, and you could make 2 of the much better panther tanks for each tiger, or 3 very efficient assault guns.
2. The tiger II was the height of stupidity and never should have been made. It had virtually 0 off road capability (I think it maxed out at around 8 Mph off road), was WAY too heavy for it's engine (the same one used in the 20 ton lighter Panther), broke down more than the tiger even, and the resources to make it, and develop it, ought to have been used for something that wasn't hideously inefficient.
3. The Panther had an extremely efficient gun and thick, but well designed armor. It was relatively fast as well, it was easily the best german tank of the war, hands down. It did have reliability issues, though not as bad as the tiger or the tiger II, and, from what I gather, they were beginning to be corrected as the war went on.
4. The origianl t-34 had a PHENOMENAL suspension and armor shape, as well as a bigger gun than most tanks of the time, but it was hideously undermined by 3 factors. A. It had no radio, meaning coordination was virtually impossible B. It had a 1 man turret, meaning the commander couldn't command and C. To a much less extent, the turret opened backwards, meaning if the commander wanted to look out of the tank he was much more likely to be killed, and seeing as he was also the the gunner, this was quite back.
HOWEVER
the T-34/85 was easily the best tank of the war. It was the original T-34 with a 2 man turret, a radio, a bigger gun, capable of penetrating the tiger at roughly 1000 yards, a respectable distance, more turret armor, while still maintaining the best suspension of the war, an ludicrously low weight per square foot, meaning it had phenomenal off road capability, and a range nearly twice what the american or german tanks had cause the russians were smart enough to put diesel in their tanks.