Everybody is going to tell you of their bad experiences with IMRF, and it does take some time and care to get the hang of using it (more than a 6 day charter) without problems, but just like a boat running aground, people run boats aground and people are responsible for any serious problems with IMRF!
Just make sure that your sales agreement has the after survey clause and that you are happy with using the IMRF before the sale is complete.