I wish I could give you the perfect answer-- we are using Infusionsoft + CustomerHub, which is NOT the best solution given they don't have a forum feature-- we have had to tack on "Tender" which is built as a support ticket/help desk engine and we've had to modify it quite a bit. I think it's ridiculous that CustomerHub doesn't have a forum given they are a membership site platform--!? Anyway, I can speak to Infusionsoft-- yes, it is expensive and yes, it is complex, but I am happy with their ability to handle VOLUME and their ability to customize and refine to infinite possibilities. There is a lot of power in that and it's built for growth and seems very sustainable. I have had a membership site for 9 years, and believe me, you don't want to move your entire platform when it becomes obsolete-- that is a huge job. You do need some assistance setting it up, but after that you can maintain on your own. I also love the way I can run multiple businesses/income streams all through one Infusionsoft account. That is valuable too. Hope this helps.