I have been using this feature for a number of years, but the Export function has finally failed for me.
I tried to Export "Genealogy of the Cushing Family 2010" that has about 33,000 individuals. Not usually a big problem, but for the past month it has been taking unusually long to download (One hour or so instead of the previous 10-15 minute interval).
Two days ago I attempted another Export but it failed at 58% complete. The program is still running a day later and it is still stuck at 58% complete.
Obviously there are some really big server and/or coding issues that need to be quickly resolved. The last time this happened (the old Online Family Tree), the entire Ancestry platform crashed and I lost a large amount of data. They said the new Member Trees wouldn't have this issue. Right. :(