There’s a “swell in griping about [Firefox]” at the moment because FF 188.8.131.52 was released so recently and this particular item has come up. This isn’t overly worrying to me because by the time Internet Explorer 7 is actually out in (what Microsoft considers) a finished version, Firefox will in all likelyhood have released 2.0 (and possibly be up to a 2.0.1 or so).
When that happens (when we see competition between FF2 and IE7… and with Opera 9, which is *also* due around the same time), the IE7 honeymoon will only last as long as there are no major security concerns… so at most a month or two ;)
Plus from all I have read, IE7 isn’t going to surpass FF (or Opera), its more like a catch-up (in terms of general abilities; there is almost no chance MS will ever devise an extension community like Firefox has). So there will likely be few people dumping FF2 for IE7. On the other hand, the inevitable press comparisons between IE7, FF2 and Opera 9 will lure many towards the latter two (and likely most, as now, will go to FF).
Expect most people on Windows to get IE 7 (as part of Windows Update), though you’re likely to still see a relatively slow, but steady increase in FF usage (with IE7 sitting idle on those HDs).
If there is any browser that has the potential to become a big loser this time, its probably Maxthon; while it offers a lot more than IE6 (using the same rendering engine), I don’t know how much more it will offer than IE7. The devoted fans will still use it, but it seems like it will be more of a niche market product at that point. Likely its userbase will plateau (similar to Opera before they removed the fees or ads in 8.5).