Great! Very happy with rash guard. Keeps cold out, easy to move around in, very light weight.
Would highly recommend it.

Good:
Very warm.
Great shoulder and arm movement.
High quality.

Bad:
Small and tight. I'm a size L and ordered an XL, but the fit is extremely tight, more like a Medium.

Heavy. That 8 oz. weight keeps you warm but it feels like wearing chain mail in the water.

Extremely itchy. The outer side of the fabric is a nice smooth spandex. The inner side, the part that grips your skin, is unusually rough fabric (polyolefin). Combine that with the small fit and it's "get this off me!" uncomfortable.


Conclusion:

Not worth the high cost. I have another O'Neil rash guard of the lighter spandex variety and they're smooth on the skin and very comfortable. Buy a couple of those and wear layers if you need the extra warmth. You can get 2 or 3 normal rash guards for the price of 1 of these thermo.

This is my first Thermo L/S Crew Rashguard and I love it.   I feel my time has actually improve and it actually keeps me sort of warm under water.

Ordered men's small. Sizing all wrong; more like a youth small. This was a gift for my son-in-law. I have returned it and will purchase a true to size replacement elsewhere.

I swim 3000 m 5 days a week and at 56 I find it hard to stay warm for the the last 1000 m in an indoor pool at 80 degrees. This did the trick. It had just enough warmth to eliminate those very hot end of workout showers.