Personally, I think Firefox 4 is a disaster. Not only it is slow and buggy, Adobe Flash has the tendency to crash once too often. Mozilla Firefox 5 promises to be a revolutionary product, an improvement over Firefox 4. Unlike version 4 which was design from ground up with a new rendering engine, version 5 [...]
Opera never ceased to amaze me with new innovative features, this can be seen with the introduction of tab browsing 15 years ago, followed by ad blocking, DNS lookup, Opera Unite server and many more. With the latest Opera 11, I can assure you they are on the path of gaining back some lost ground. [...]