At our consulting shop, we have always done this in house ourselves. However, we have a few clients who were using datafeedwatch and it worked out quite well. I am sure the other solutions are great as well. I would make sure you focus on accuracy of data, its depth and go through as much as you can with a fine comb so that nothing is missing. Its easy to get lost in a big data set.
Feel free to reach out if you need help.