I found the Tet tough to play....just didn't suit my style. It can be a pretty tough tank in the right hands, though. I've been killed by enough of them. I'd build up all the Tier I tanks to elite and then see which direction you want to go. I'm playing primarily US right now, but I do have a Pz38t and a T-26 in my rotation.
Edit: If you end up finding that you don't like the Tet, it's worth 150K when sold.
'09 Kawi Versys
"A life is like a garden. Perfect moments can be had, but not preserved, except in memory. LLAP" - Leonard Nimoy