I did an experiment for you today. I had some lychee tea left from Upton and Dragonwater and I brewed them side by side according to the same parameters. Conclusion: they are the same tea. I think Dragonwater either buys some of their tea in bulk from Upton or they have a supplier in common for some of their tea. (Also see: Turkish Apple tisane from both of these companies.)
I've also recently tried some lychee teas that I cannot recommend. Enjoying Tea's lychee oolong
and Tea Logic's lychee black
have simliar flavoring that doesn't taste anything like lychee to me. More of a general fruit punch like sweetness, which is too bad because both vendors sell some very good teas. What's worse is the oolong's base tea comes out nasty when brewed, although Tea Logic's black tea is good.
Indigo Tea's lychee
has also been recommended to me, but since 4 oz. is the smallest size they sell I haven't bothered ordering from them yet.
Please post your thoughts on the Teacuppa or any other lychee teas you try!