It is thought you need to have multiple estimates to judge how much your job will cost.
IF every estimate was written the same and covered exactly the same items, and promised the exact same outcome it would be fair. BUT cheaper isn’t always the best route to go nor is the most expensive. You need to have a price in your head of what you can spend. You need to know exactly what you want done and you need to read the estimates carefully to make sure everything is covered. Did they include the removal of trash? A port-a-john or will they be using your bathroom. Material supply prices change monthly so is there a time frame for the quote or did they pad it enough to cover increases? Remember you are paying someone to do work for you and they are entitled to be paid for their time and expertise they bring to your job.
Most estimates involve 3-15 hours of work on spec. Would you work for 15 hours for free? So please be considerate and get back to the estimator. Good & bad feedback is always welcome. Also talk to them if there is an issue, it may be written but it is not written in stone. Until it is signed, every line can be discussed.