I think the five star reviews are there just because it's firefox and for some reason people seem to think it's the superior browser, regardless of platform. I attribute it to the fact that firefox on the desktop pretty much saved the day when IE was total crap. Also the anticipation of flash plugin probably doesn't hurt the score either.

That being said however, I agree with you. This incarnation of ff seems too laggy to use. Opera is better, but I still prefer the built-in browser. It has its shortcomings, but it's still agile and very useful. I don't expect desktop browsing experience from mobile browsers, but I want usability. I don't get all the bad feedback and the mocking the built-in browser has been receiving. I think people are judging it by the feature list instead of the browsing experience.