While all companies may say that they can do the job for you, not all will perform the job equally well. Learn how long they've been in the business and find out what work they have done for companies that are similar to yours. Given what's at stake, you don't want anyone to learn on the job. And of course, there's the issue of price. Recovering from a disaster can be a costly process.
Prices vary according to the corrosiveness of the soot and the extent of the water damage.
But don't be swayed by the lowest price bid. Dig into the restoration process. Find out what methods the companies employ to recover key files. Where one company may air dry wet papers, another may freeze the same documents. At this stage, effectiveness is probably more important than cost.