SEOmoz, blog for search marketer professionals have covered Groowe in the post 14 Popular Browser Toolbars Reviewed - The Worthwhile and the Worthless.

From the article:

Features:

* Search multiple engines and vertical sources
* Get the Toolbar Functionality from Google, Yahoo!, Live, & Ask by rotating through
* Set preferences & add custom buttons & sources

Value to Ordinary Users: Medium to High

If you’re a power searcher or simply want to have multiple toolbars without the massive visual space consumption, Groowe is a solid choice. There’s a lot to like here, but you need to be someone who’ll actually use the features, which many ordinary users might not. Still, of the search-focused toolbars, Groowe is certainly a standout.

Value to Web Professionals: Low to High

Depending on what you’re doing as a marketer or developer, Groowe could be a boon or simply a replica of some features you’ve already got. The toolbar has a lot to offer, but again, it’s going to be personal choice & habits that make it valuable. My feeling is that marketers, particularly search marketers, will find more value than developers, who probably don’t need the extra search abilities on demand.