I've been seeing the need for this for a long time. Googlebar Light is great, but I hate being tied to one search engine.
The current version has issues. I should report them on the web site, but, well, that's the first issue:
-- The official web site is a mess, with broken links, and no feedback forum. And pages that link directly from the toolbar give a 404!
-- The thing installs with a blatant ad for Amazon.com. You can turn it off, but it's still inappropriate.
-- Some buttons are managed through the usual customize wizard, others are toggled on and off by options. Confusing.
-- Search text buttons are the main reason I use a toolbar rather than FF's own search widget. The traditional implementation, where each search term becomes a page-search button, is simple and effective. Groowe, alas, uses a drop-down menu. That's more complication than I care to deal with.
-- The idea of automatically changing search engines when you enter that engine's web site makes no sense to me. The whole idea of a search toolbar is to allow you to perform a search *without* the extra step of going to a web site. Maybe it makes more sense to some users, but the feature still needs to be optional.
Despite my carping, I see the basis of a really great toolbar here. I look forward to seeing how it evolves. It wouldn't take a lot of improvement to make me switch.