Nice! What location was the house in? And do you feel like you underpriced it? An all-cash offer is the right choice for sure, so much added risk with the contingencies.
We just sold our house in three days, for asking price, but we purposely dropped that price to move it fast, and it is working out great (so far anyway). I just traded some emails with the buyer, and offered him a bunch of our furniture, power tools, and assorted crap that I would have had to Craigslist before we moved... he bought almost all of it, add another $5k to the pile. Feels great to get rid of stuff.