Ive built few stores 7 years ago using spree and solidus.. They were like 90% match.. I even could use same extensions on both! After all of these years i noticed sone dramatic changes, in core and direction! I would say, each can fit certain needs and requirements.. I don't want to install both and try every single feature or whether they offer certain setup. Is there a comprehensive comparison list for exampke that can tell which solution fits what? based on requirements? Which best for saas? Which gives more dynamics to do complex customization? Which offers more extension support!

Honestly not an easy answer. Also, it will be very biased. My observation is that Spree concentrates on Easy to Install and be better used as SaaS vs. Solidus has more manual work involved and has better customization for complex setups. But take this with a grain of salt. I have not used Spree for several years.

There's a lot of ways to compare Solidus and Spree, but I wrote up a short blog post on the biggest reasons why I continue to choose and support Solidus. Hope that's helpful. https://supergood.software/solidus-versus-spree/