I am a fan of GPLv2, and commonly apply it to my work when there is a free choice. I’m not sure about v3: I need to find time to read what it’s finally become first. But I have a gut feeling, which goes something like:
GPLv2 – a work of genius.
GPLv3 – a work of committee.
Now I see Anthony Towns blogs about what looks like a very nasty gotcha: LGPLv3 incompatible with GPLv2. If he’s right, that’s likely to cause serious grief not only in the pedantic camp (Debian et al), but also in the centre ground (Redhat, etc). Who foresaw/intended that?
But such an incompatibility also feels like a suicide note for GPL as a mass-participation movement. As of now, the GPL has a very long tail: independent developers (such as Yours Truly) licensing works under the GPL. Most “long tail” works may have little or no value individually, but the tail as a whole comprises a very substantial body of work. Not everyone in that tail is going to pay attention to the nuances of a license change. I expect we’ll have chaos, and a lot of unnoticed technical violations.
That looks like fertile ground for lawyers when someone big and serious – for example Microsoft – wants to fight the GPL.