I have been there many times (around 15 times), most of the times I spent 1 or 2 days (crew member layover). I only stayed in Dhaka (the capital). Last visit was 5 years ago and once my seniority in the company was better I stopped going there. I do not have much to say but I will try to sort the things I have experienced there which unfortunately are negative in general:
- Not safe at night. I was about to be beaten at night in attempt to steal me.
- I had food poisoning twice, and that was from the hotel food! and that was a 5 stars hotel. I do not want to imagine what kind of problems would I get from street food.
- Hotel water was yellowish...
- Traffic was an issue, people drive badly. I almost had an accident while in Riksha (Rickshaw).
- Strikes are so common there. I had an extended layover there (4 days) because of a major strike. My Embassy sent us a warning not to go out during that. In total I experienced 3 strikes there!
- There are many beggars almost anywhere you go, if you give one, the rest will come to you. They will follow you even after you are inside your car. That's a nightmare for me.
- Streets are super dirty...
- Do not go in the rain seasons. Floods are common there and they are dangerous.
Anyway, the prices are cheap there, you can do a lot with little money. Try to go to Bango Bazar which is a local market that sells clothes for well known brands at very cheap prices like 4 or 5 USD for the piece. They have factories there for the major clothing brands and the rejected or defected clothes are sent there (minor defects that can not be seen by the eye). There are some modern malls there.
I'm sorry I have said a lot of negative things but that's out of my personal experience and I haven't been to the countryside of Bangladesh so I hope things are better there.