There is not enough information here to give you an answer that might be the best fit for you. How much do you owe on the property? Are their rental payments covering your cash flow or are you in a negative cash flow each month? Do you have plans to invest in another property should you sell?
Do your renters need to get a loan? Would you be interested in doing financing for them, where you could make more more money from the interest payments than you are making now. Sometimes price can be reduced should you realize the return you could get by doing this and not have to pay property tax's and other costs of owning. Since this is not your principle residence you need to talk to someone who could help you run the numbers, if you sell to them you could be saving in real estate fee's, have an agent do the paper work help with escrow for a set cost less than what many attorney's charge around 10K. Sounds like you have interested buyers now, is their offer way to low? They could be just testing the water and why not counter back to them and work out some terms if you can get them to come up in price? Why would you wait it could be a long time for the market to change.