ISDK

ISDK is a team of 30+ professionals specializing in e-commerce and custom development based on Microsoft technologies. In practice that means running an online store from catalog to checkout.

It makes the most sense for retailers and brands. Alongside the main category they mention E-Commerce and Retail. As a small product team themselves (11 to 50 people), they tend to serve customers of a similar scale best. You will probably talk to the people who build it, which is great until you need 24/7 support.

ISDK is based in Austin, Texas. Their site is isdk.pro.

Things worth asking about: transaction fees, themes, and app ecosystem. Ask for a trial on your own data, not a canned demo.

Every review on Revaw shows how it was verified, so if you know ISDK well, your review carries weight here.