Loved my stay at Julie's Cabins. It's clear that a great deal of thought went into making the whole experience comfortable and relaxing, even small details like the way the chairs are designed. I'm not really an outdoorsy type, but I spent a lot of time just hanging out on the porch and swing hammocks, bird-watching and reading, enjoying the beautiful weather. The fire pit was a real treat in the evenings, and the heated swim spa was surprisingly fun, especially after sunset on a cool spring night.
Amenities were thoughtful and well-stocked, including several things that I forgot to bring (bath soap, shampoo, towels, coffee, seasoning), and the shower was nice and hot. Tad was very responsive and welcoming and just seems like a great guy. If you're looking for a cozy "camping" experience in Austin, you should definitely check this place out.
Other considerations: It's just a 5 minute drive to the Jester King Brewery (closed Mon/Tues), 12 minute drive to the Austin Zoo, ~20 minute drive to the Wildflower Center, and ~30 minute drive to downtown. So it's a great way to visit Austin if want a rustic escape from the city in the evening.