I've been using Fort Awesome for 6 months and I'd highly recommend them. For $50/year it's a steal.
My favorite workflow is grabbing an svg icon from Noun Project, modifying it in Illustrator until it suits my needs, copying it (Cmd + C), and pasting it directly into the Fort Awesome import box.
This has all the benefits of generating svgs on your own with very little downside. It's saved me a lot of time and it makes turning an app design into a finished product a much faster process.
They also just bought an icon design studio, Symbolset, and include many of their icons in the Fort Awesome icon selector: https://symbolset.com/