I am wearing a Rowena for my 100-day challenge, and I needed an extra layer to wear underneath since I am COLD in Ro's thinner fabric. I initially ordered a Black tank in XL based on the size charts, but it was too loose overall. I exchanged for a Large and am very happy with the fit. It is close-fitting but not snug, a perfect extra layer under my dress. The fabric is very thin -- it's absolutely meant as a layering piece, not a stand-alone tank (which is stated in the description).

I can wear it day after day without it smelling, just like my Ro. The ONLY downside is that I have a long torso and I wish it was about 2" longer. I've been tucking it into my Axis leggings under my dress. I will order a second at some point in White for layering under my Maggie and Willow!

I bought the Natural White tank in large to have some looseness and length to cover my butt in leggings. The material is nice and the V-neck/scoop neck reversible feature is great. I am surprised at how thin the tank is, though. It's basically see-through. Will use this to layer but can't wear it on its own which makes it less versatile than I was hoping.

if you are someone who is always cold, this super light under-layer is so soft and warm, yet when the temperature changes no worry about sweating as it is breathable

I got this to wear under dresses and shirts that are a bit too low. I read the reviews and decided to go with a medium, but I wish I'd gotten a small. It gapes at the front when I'd rather it sit snug on my chest. It's a great quality for a layering tank, but I wouldn't want to wear it without something over it. For reference, I'm a size medium in Fiona and Stella (loose fit), and a small in Maggie, Camilla, Summer Midi, and Cora.

The essential has been great in very hot & humid weather.
I purchased a larger size because I want a straight fit that was not body hugging.
Shortened the straps and took in sides right below the armpits. This created a pretty neck line on the round side, and the v-neck side is not too deep now.
It handles the sweaty weather better than I do.
I look forward to layering with it in cooler weather.