Yes. First, the formal version number is three parts (I don't see a three part option in your poll suggestion, but I may have read too quickly). Second, and far more importantly, every part has a strictly defined meaning. There are lots of variants of x.y.z version numbers, but this is the only one that at least purports to address the issues of dependency hell. For example, it is incompatible with Perl 5's numbering, which uses the y part to indicate whether a version is a development version or not. But it is a formal spec for version numbers, and I like having that sort of spec available. It's the spec that makes it different from your options (at least in my eyes), not necessarily the layout.