I ordered the Men's Tri Aero Jersey using the size guide. The jersey fits perfectly and is lightweight. The jersey is also comfortable.
I love my Mach jersey and would buy another one. The down side is the time it takes to get it.
This was the first quality race kit I've purchased. I've been able to test it cycling and swimming. I love how good it looks and all the designs Mach makes with their apparel. The other aspect that is striking for me is the comfortability of the suit. I'm a big supporter of the company using recycled plastic to make these suits as well. All in all I would happily endorse Mach's products.