@targhan
I think that £35 is more then fair for a piece of software. The biggest problem is that we are so used to web browsers going free (Netscape, IE, Mozilla) that we forget that it does cost money to make a complicated program such as a web browser. And seeing as the guys who make IB probably don't have a huge financial backing from other projects, this may be the only way they have to finance the project.
No doute IB is far from complete when it comes to features (but then in the ever changing world of the Internet, which browser is?) but if enough people show interest, and more importantly buy it, I am sure those features will be integrated into the program.