I think that people get into trouble when their expectations don't match the "realities" of a resort as they see them.
The negative reviews that you referenced seem to fall into that catagory. The people who wrote those reviews felt that Bandos didn't meet their expectations of what a 4 * resort should be. Actually reading through the reviews there are positive reviews where people suggest the same thing.
Obviously 4 * is somewhat subjective and depends to some degree what the reviewer has previously experienced.
In my view there are two issues for you to consider. Bandos is a pretty large resort. Bandos is a resort that attracts families.
Depending on the staff/guest ratio a large resort may sometimes suffer in quality of service compared to a smaller one. On the other hand it can just be that you happen to draw a less experienced or less motivated room boy or waiter which can happen any place. As for the family issue I think you probably will find that less of a "problem" based on the time that you are going to Bandos and your choice of Beach Villas. To some degree you do get what you pay for. Bandos is a quality resort for the price that they charge.