Reasons I do not.

Firefox 3 is about to het the Internet tubes in a couple of hours. Great, or is it?

The fact that Google Browser Sync project is not taking calls nor displaying any word about support of their essential FF extention for FF 3 has made me decide to NOT upgrade.

As much as I liked test driving FF3 [all beta's and RC's] I just do not want to browse without GBS, unless I am given no option.

So here is my appologies to the FireFox 3 team: sorry! But I will retreat my pledge to download FF3 untill GBS is available and will continue to use FF2.

Here's the google teams reply:

Thanks for trying out Google Browser Sync and for all of your feedback. It was a tough call, but we decided to phase out support for Browser Sync. Since the team has moved on to other projects that are keeping them busy, we don't have time to update the extension to work with Firefox 3 or to continue to maintain it.

For those of you who want to continue to use Firefox 2, we'll maintain support for old versions of Google Browser Sync through 2008. After that, we can recommend a few other products that scratch a similar itch. We hope that one of them works for you:

Mozilla Weave [labs.mozilla.com] from Mozilla Labs—Offers bookmark and history synchronization across computers.

Google Toolbar for Firefox [toolbar.google.com]—Store your bookmarks online and access them from any computer online.

Foxmarks Bookmark Synchronizer [addons.mozilla.org]—Synchronizes your bookmarks across all computers where it is installed.

Regards,
The Google Team

But personally I do not want to change too much at a time so I will sit back, enjoy GBS for the comming couple of months, wait till FF3's bugs will be ironed out and then, maybe, switch away from GBS to one of the above mentioned 'replacements'.