I've been drinking flavoured green teas for a couple of weeks now but cant say I've noticed its affected my losses at all (had 1 1/2lb loss and a STS since I've been on the green tea - had a posh meal out on the STS week).
I will keep drinking them though - I like them, and it frees up some milk allowance to use on other HEA choices.
At work I have a pack of Twinings mixed flavours - 25 bags with cranberry, citrus, pineapple & grapefruit, apple & pear and orange & lotus flower - quite good to get a variety of flavours and decide which you like best. At home I have green tea with peppermint.
I don't have any standard green tea, I generally prefer the flavoured ones. I take it without milk or sweetner (but I dont sweeten my regular tea anyway)