This page is no longer actively maintained. (Pardon?)
From what I've heard, the Zenit-TTL didn't evolve from the Zenit-E as is commonly believed, but from the Zenit-B. It appears a KMZ engineer named Valentin Chugaev built a TTL metering system into a stock Zenit-B in some lost hours, and managed to convince his bosses that this was the next step forward. Not that they probably needed much convincing, since the mainstream camera industry (the free market one, I mean) had embraced TTL SLRs years before. (SLRs and TTL metering are a match made in heaven: not only do you see through the lens, but you meter through it as well.) The TTL was produced in the Krasnogorsk and Vilejka Zenit plants for over eight years, with a grand production total of over two and a half million.
The TTL is a decent camera. It's basically a Zenit-E with fancier knobs and TTL metering, which is both good and bad. Good because SLRs don't come any tougher, and the TTL with its one piece cast body is a hardened ruffian. Bad because, well, it's a Zenit-E. At least KMZ got the ground glass right this time. Buy one of these with the nicer of Soviet lenses (I'm thinking the Helios 85mm f/2), and you'll have a cheap but potentially very good camera. (Potentially.)