Based on your answers, my recommendation for your business is ConvertKit!
First of all, congratulations! You are serious about marketing and are ready to step up your game. It's likely you've been in business for a while and understand the importance of segmenting your list.
ConvertKit is an especially good option for bloggers and content creators as they have built-in opt in blocks that can be added directly to your content.
I will caution you… ConvertKit only handles email marketing. If you want to do anything more advanced like accept payments, run a membership site, or create your own affiliate program – and do it all in one place – you'll need to make the step up to Ontraport.