I have faced this question countless time and there are two facets to the answer, one is technicalities, like:-
- If you have all your bugs worked out.
- You are ready to create a new version (revision change).
- You do not anticipate new changes for a while.
- You are taking money for your product.
Each of these answers have great merit and all could justify transition from Beta to release.
However, there is one key thing that everyone overlooks:-
I would suggest that this is not a technical question but rather a marketing question.
It comes down to one thing: Will removing the beta tag improve your position in the marketplace or detract from it?
In the example given of Gmail, the marketing decision seemed to be that stability is very, very important to Google so they kept the beta tag for ages. For others, the projection of stability may not be as important. So in other cases, if buyers would be reticent to pay for a “mere” beta product, it may be time for the tag to go. Determine the marketing benefit/risk of removing the tag and act accordingly.