I usually drink decaff, and there's definately a difference, as there is with decaff and normal coffee - all brands. It wouldn't put me off it though.
In the 'olden days' the decaff tea wasn't readily available as it is now and you had to get it from a holland & barrett type health shop - It was some specific and weird 'health' brand which was virtually tasteless, but things have moved on since then.
You won't find one that tastes exactly the same though.
We've only drunk decaf tea and coffee at home for years now and I can honestly say I don't notice the difference in taste when we have the full hit stuff when out and about.
Try all the different brands, I'm sure you'll find one you like. I wonder whether it's psychological to an extent, and that if you didn't know you were drinking decaf you wouldn't actually notice the difference in taste. Just a thought.