The short answer is yes. There were concerns. Aung San Suu Kyi herself highlighted some issues of concern—people who were apparently dead who were registered to vote, these sorts of things.
One could get into various aspects of the electoral process in each and every one of the electoral districts, but the result in many ways spoke for itself. If there was election rigging going on of any significant dimension by people who had a stake in rigging those elections, they certainly failed. We had monitors on the ground who reported that it looked fairly good, but they didn't have proper access; they were observers more than monitors. This was not a process that was really scrutinized in great detail by experts in the area of election monitoring.
I think the simple answer to the question is that the results speak for themselves.