Really pleased with this product. I'm 5ft 8'' and a medium fit was perfect for me. Product has good length but I'd say go for a larger size if you're in between sizes as I think it's on the tighter side.

6ft medium build and orders a medium.  Can’t fault this top. Snugly fits the arms and upper chest whilst still having a breathable feel to it. Slightly looser round the mid section which for me is how I like my tops to fit. Stretchy fit so plenty of room for movement. Collar for myself was snug but not restricting so I would say any smaller size could be too tight.  This to me is very close to being on par with the likes of Nike. A slightly thicker material would match that standard. Love how the branding is also minimal as for me any big brand logo are a no go for me.