Embers, nice people and quality kit through and through. They'll give you as much advice as you need, good returns policy if it's not what you wanted, they appreciate feedback so the range is constantly evolving. I don't know where you are, but they're in Derbyshire (Belper) worth a visit if you're in the area, though they don't keep regular shop hours;
http://www.embersmerino.com/
My experience with merino is that it's certainly not all the same. Howies, Icebreaker and Embers have proved to be excellent, the cheaper stuff from Planet X and Endura hasn't been as good, not as soft, sometimes itchy and isn't as easy care. I bought three Planet X T shirts for the price of one Embers, I'd rather have the one Embers.
Bamboo probably also comes in different grades, the one T shirt I have is soft and nice to wear but takes too long to dry to make it practical for touring.