I use Ext Designer daily (latest version) and I find that it regularly crashes. This, I believe, is due to the size of my project file (around 1.7mb).
It wouldn't be so bad, but when crashing (especially during saving), it wipes out the entire project file (bringing it back to 0kb). Fortunately I have hourly backups, but still not desirable... it kinda puts fear in your heart every time you hit the save button
The product, otherwise, is awesome.
If something could be done to improve support for large files, that would be great.