Just update to the latest git revision (ec5396c85cd7e0d8c226cc2884608b5a71bd9a23), the resulting guvcview has a very low fps (~5). However, package built by my distro has the maximum fps (30). The only interesting debug message is this:
GUVCVIEW: couldn't read line 46 of config file: File exists
But I have no idea which config file this is.