Icebreaker is a quality brand. I've recently bought two items online. A fairly lightweight thermal long sleeved base and a pair of running shorts.
I must say that buying clothes online is not the same as buying them from the shop so if you can find an icebreaker in a shop before you buy it online so you know exactly what you are getting.
I am not complaining but neither are quite what i expected.
once before i bought a base layer from wiggle online. I was disappointed with that because a) it was shorter than i thought it would be (on the basis of the diagram) and b) it had moth larvae in it and so i've been getting holes in it ever since. Also its a bit scratchy which surprises me for superfine merino.