I've officially shut Quote Calculator down. After a couple of months of thinking back, I've come to the conclusion that while I believe I had a good product, I've fallen into the oh-so-common trap of not validating the market enough before investing countless hours into development.
The one thing I should have done before building such a large scale product is speaking to the target markets that I had identified, showing them wireframes and asking if people would use and pay for the service.
Another thing I would do is to try and take pre-orders, get 100% validation that the tool/service is useful and would be paid for.
While this didn't work out for me, I'm actively looking into another 'thing', whether it be SaaS, product or just a simple plugin. I've got the bug again and will be back.