What's everyone's take on online vendors (big cartel, shopify, etc.)?
Which ones do you like? Why?
Also, which do you feel are best for customization? (this more than anything)
There are so many options out there, but you need to determine which platform is the best when it comes to catering to your brand's needs. Some factors to consider are storefront customization, CMS, product limits, payment options, scalability, analytics, marketing, and plenty more.
BigCartel, Storenvy, and SupaDupa are all great options for a smaller scale brand. BigCartel and SupaDupa are a bit more flexible when it comes to customization, but Storenvy's advantage is that they have a close, friendly community (very similar to Etsy's) that gives individual shop discovery a little boost.
Platforms like Shopify, OpenCart, Magento, and Spree (and hundreds more) have a more extensive set of features that allow you to do more complex things with your store. Some include affiliate programs, loyalty programs, social media connectivity, automated SEO, giftcards, and abandoned cart email.
I have experience working with a large array of different platforms, so if you want to chat some more feel free to hit me up at firstname.lastname@example.org.