I won't bother with all the quoting for sake of time (gonna be a book anyway), but to answer some of the items the two of you said:
First, don't go by the History Channel for much other than "that sounds interesting, I wonder if its true." Their top 10 tanks were a joke. They actually stated that the T-34's "high velocity" 76mm gun was able to penetrate the frontal armor of the German Tiger at range. That alone tells you how much they fact-checked that particular program.
Second, the T-34 does NOT have "way more armor" than the Sherman. What it does have is better slope and a lower silloette, which made it harder to spot, and harder to hit squarely, which meant more propensity for a round to richochet off instead of penetrate -- at least for the lower calibre German guns of 41-43. By '44 the 75mm and 88mm guns cut through the T-34s as readily as they did the Shermans.
The 76mm Soviet gun and the snub 75mm were about equal IIRC. The Sherman benefited from a much roomier turret which meant a much higher rate of fire, and had much better visibility for the crew.
The T-34s were inadequate by 1944, hence the upgrade to the T-34/85. The 85mm gun was a very good gun, and made the T-34 leathal again.
IMO neither tank deserves its reputation. The T-34 built up it's reputation as an "uber-tank" because when introduced in late 41, the Germans had nothing to compete. The PzkwIII of the day had a 37mm gun (some upgraded to 50mm) that were inadequate to take out the T-34. Most Pzkw IVs still mounted low-velocity howitzers for direct infantry support. Thus, in tank vs tank battles, the T-34 did dominate for a time until the Tigers, upgunned PzkwIVs and Panthers were on the field in enough numbers to counter. By that time, the T-34 was already the darling of the Soviet tanker, and couldn't be blamed for losing against the German heavies.
Well, you know what, the Sherman was introduced in 1942, and at that time was better than the Pzkw IIIs and IVs as well. But tank vs tank battles of any scale did not occur until 1944 in Normandy. At that time they faced upgraded PzkwIVs, Panthers and Tigers. And these tanks made short work of the Shermans, just like they did on the East Front against the T-34. But, since the majority of the American servicemen did not see action until Normandy and after, their impression of the Sherman was that it was inadequate, a death trap, etc. and couldn't stand up to German armor. Hence the reputation.
One final thing that did hurt the Sherman was US armored doctrine. The Shermans were supposed to be direct infantry support vehicles, and were not supposed to fight tank-to-tank combat (but try to tell that to the guys in the field!). In this way they were similar to the early German PzkwIVs. The US instead designated tank-destroyers for the roll of tank-vs-tank combat. In practice it did not work well, but that was the doctrine. The snub 75mm gun was not designed to be an effective tank-killer, but was adequate to take out the lighter-armored PzkwIIIs and IVs the designers new the Germans had. They did not contemplate the Tiger or Panther. (Even the high-velocity 76mm guns on the tank-destroyers were inadequate for these when hitting the front, which goes to show the US did not foresee very heavy tanks).
So, the Sherman is only a "bad tank" insomuch as the M-60 is a "bad tank" because it can't stand up to the M1 Abrahms. Armored innovation simply out-paced it. But, it did what it was designed to do, did it effectively, was easily produced, was mechanically reliable, and was easily modified to fit a variety of rolls (dozer, crab, calliope, DD, etc. all based on the M-4). "Reputation" is a tricky thing to base assessments on, because they are often proved wrong when looked at objectively.
