ad blockers have a tough fight to gain widespread usage, specially because ads are the de-facto monetization strategy, plus they are so easy to use.
A service such as yours offer the value of not showing ads, which for some niche is something worth paying for, so a subscription based service seems natural.
Think of ads as spam. There are a ton of spam filters, nevertheless spam cannot be eliminated completely. Ads are even harder to remove since they represent a revenue stream. THE revenue stream online.
It's a about a blog entry of a self taught programmer who was changing technology stacks back and forth, I suggest you to read it.
As he concludes, the answer is to focus. IMHO if you don't enjoy .Net and you want to change it, go for it; you will need motivation along the way and if certain technology doesn't give it to you then learn something that does and STICK to it.
Thus far, we've been working with hedge funds/ banks/ schools and have provided specific tutorials to them for their specific contests. But you're absolutely right, and we're working on a site-wide walkthrough for first-time users.
A service such as yours offer the value of not showing ads, which for some niche is something worth paying for, so a subscription based service seems natural.