No I don't consider the problems to be fatal errors, in that it screws up your data, but to be very irritating.
I have to restart it after a few data updates because it starts to not work correctly. The first sign I see is when new image thumbnails are blank. Or when the merge box doesn't update when you click on a new person in a record.
Please don't tell me that Ancestry is providing support for these problems. They are NOT!!! No amount of have you tried this or do this will fix program software errors.