I compared fiber glass insulation vs celluous insulation and found that celluous is very good as long as you do not have a leaky roof. Celltech gave me a very honest answer to all the questions while his competitor is very discouraging. The competitor beat up on celluous while celltech just explain the pros and cons of each product. Celltech also gave me a very good quote (the lowest price). I were worried a bit how they will make a mess in my closet (that's where my attic access is), but they were very careful. They even brought a roll of thin poly to lay down for the dirty hose to go on. Overall I was very pleased, they got in, got the job done in about an hour. cleaned up and all done. There is definitely a difference in comfort level upstairs compared to before.