I've used it without problems so far, but I went to adjust the level of an amp block which was too loud, and Axe Edit told me it was at -53. A couple similar other anomalies have scared me off using it until they've worked it out.
On one hand, calling the editor 'free' is missing the mark a little. You can't include all the updates and the editor as part of the value of the product and then say it's free so you can't expect it to work. Part of the reason people buy the axe fx is the ongoing updates, support, and ability to edit with Axe Edit. On the other hand, I don't find it surprising that there would be a few bugs with it working with the new BETA version of the firmware. They told us this was a beta, which should prepare you for the possibility of a few minor bugs. I'm sure they'll work it out and have the Editor or firmware patched up soon, and the world will continue to rotate upon its axis.