That's the reaction I had to the Tazo Iced tea sold at cooking.com the first time I made it. I got woozy and a little nausea kicked in... I think it was overly caffienated. I know it's sold at Starbucks as their house iced tea, so that would make sense.
When I was at the airport in Kansai Osaka, Yuki bought me one from a Starbucks and I was suprised that it tasted exactly the same as what was in my cupboard back in the states (it was about $3 for a little plastic cupfull). I don't know why it was suprising, but it was.
I'm pretty good with most black teas (in fact I drink black tea regularly), but some of the really strong breakfast blends I just can't stomach.
I've had bottled Tazo and it works fine for me. I haven't bought Tazo for my home enjoyment because, to be honest, I can get other teas I prefer. I love Adagio's Oriental Spice as an iced tea with a little raw sugar.
Well, I'd be surprised more if the Tazo tea didn't taste the same in Japan. That's one of the big positives to franchises and to brands. (It's a negative too in many ways). You get what you expect every time. Or should.