I used to drive the T34/76 before the 85 came out. Before that patch it was way easier to take down a base's ack and camp the runways with the T34. Since that patch they made it so the tracks get blown off way easier by base ack.
Here are my views on this tank:
It's fast. I really like that. The turret traverses faster than any other turret in the game, and that really, REALLY rocks.
The main gunsight is like looking through a straw, but if you are really adept at switching back and forth between the main gunsight and the commander's cupola thingy really well you can see what you need to see, and get your gun on target well enough.
The gun elevates really high comparatively to some other tanks, which makes it really good for shooting down IL-2s, B-25s, and anything else that tries to strafe you from too low an angle. With practice, shooting down these low-angle strafers becomes trivial. Pintle gun? Bah! Use the freaking cannon!
Camping an airfield in this tank is complicated by two things: it dies very easily to manned ack, and the VH only stays down for 15 minutes. You have to be exceedingly vigilant in killing the manned ack, and if you succeed in killing the VH you've got 15 clear minutes. Then, if you don't have help, it's probably game over. Sure, you can shoot down the Panzers easily enough, but Shermans, Tigers, and other T34s, shooting from even close range from behind, you'll shoot out some turrets and some engines, but they'll just keep landing it safely on the little dirt road in front of the vh where they spawn, and re-upping until they manage to get away, and then you're finished.
And if you try to camp them from the side, sure you'll get some more kills, but they'll spawn sometimes and get their gun traversed around on you before you even see them appear, and shoot out your turret or kill you. And the T34-76's gun reload is so slow that if more than one person is trying to spawn and kill you, it's just a matter of (a short) time before they succeed, even with Panzers.
You can kill Tigers with the T34-76, but they either have to not have the SA to know you're sneaking around on them, or be so engaged with other people they can't stop you. If they know you're coming it's very difficult. The biggest thing you have going for you in the T34 vs. the Tiger is that the Tiger turret is so molasses-slow that you can actually drive around the Tiger in the T34 and stay ahead of it for a while. Except for freak-lucky shots, which do happen sometimes, I don't bother shooting at Tigers at ranges further than 400 yards or so in the T34/76, and then only if I'm shooting at the side armor from 90 degrees, or into the engine, or side or rear of the turret.
They key is hitting the turret from the side or rear first. Always, always, always go for the turret on a Tiger when you've got the drop on one. Then kill the engine, then hit it from the side until it blows up.
Sadly, a Sherman is basically a Tiger when you're in the T34/76. You basically can't kill the Sherman turret from the front for some reason, and the frontal armor is not totally impervious to the T34's popgun, but might as well be. It's side/rear turret, and side/rear hull shots. The big difference is that you can take out Shermans with side hits at over 800 yards with the T34/76, but I don't try that against Tigers.
The bottom line is that against Shermans and Tigers, if they know you are coming, and they are good tank drivers, your chances are very, very low. They basically have to make stupid mistakes if you are to have a chance. I can kill a lot of mediocre drivers in my T34 and them in Shermans and Tigers, but the really good drivers - not a chance.
Oh yeah, I second the suggestion of using HE rounds at the tracks to disable the Sherman or Tiger that's at longer ranges. I've duked it out with Shermans at longer ranges before where I had no choice to get away, and used HE rounds right at the tracks or next to them on the ground, and disabled them that way, and that really gives you a chance to get away or get around and hit them from a vulnerable direction.