This is sooo comfortable! Compared to merino base layers I have from other companies, it is a much softer knit and really comfortable to wear, not at all itchy.
It is super breathable, and I wore it on holiday in the UK for 6 days in a row, through rain storms, icy cold winds, and hot and sweaty walks. It didn't get smelly, I didn't feel clammy and uncomfortable, and I didn't feel cold.
I like that the neckline sits really well under the Sierra dress (see photo).
2 small gripes - the should seam doesn't sit flat (see photo); and the colour "Marionberry" comes out quite differently in the Sloan to the "Marionberry" Sierra (see photo).
I am a UK size 8-10 and the small fits perfectly. It's not skin tight round my waist, but it's a snug enough fit for keeping me warm.