We're looking for tax compliance software and even when we talk with the biggest players like Avalara, Vertex and Sovos, the lack of knowledge (even about how there own software works) is astounding. We actually signed up with Avalara, but between not being able to answer many of our questions and waiting weeks to get a reply saying they don't have an answer, we're already looking for another provider and we haven't even gotten Avalara implemented yet!.....
We've also been talking to TaxJar and they've been much better at getting us answers, but to be honest, that the cost of TaxJar is so much less (a third to a quarter of the others), makes us concerned that we won't get all that we need. I'd love to pay less, but in the end, we need software that does the job and support we can count on.
In any case, I'm very interested in hearing how TaxJar is working for anyone using it and feel free to pm me.
FWIW, we're a manufacturer and our sales profile includes consumer sales off our Magento site, Amazon Seller sales and wholesale business to other retailers that sell our products (some of which we need to charge sales tax on because of dealers who don't have resale certificates).