Well yes, I think the Americans summed it up as a well-designed tank that lost most of the advantages of its design to atrocious quality control. But the Sovs made enough of them to be effectively disposable, so if you broke one you just got another. Quite similar to the M4 and the PzIV in that all were fairly good tanks when they first showed up, hopelessly outdated by 1945, but the production lines were there and ready and their replacements were expensive and hard to build. (The M4 was really slow to get off the ground though - you could argue it wasn't even that great brand new, though if it had showed up at the same time as the T-34 it would've been great)
Besides, they'd knocked most of the kinks out of the production process by '44 and they were likely to actually be driven to the front instead of breaking down before they got there. Their vaunted reliability didn't exist before then, really. Bad welds, engines that caught fire, most of them leaked in the rain...