I don't know about reliability, but I do know that GM's for the most part are relatively cheap to maintain(which to some is more important, like me). I'm not worried about reliability personally, don't know why, maybe I'm just too trusting of GM.
If you want to get an "idea" for the reliability of the zeta platform, check out ratings for the Commdore on some of the Aussie car sites, like Drive.com.au(
http://http://www.drive.com.au/)