The problem with system restore is that it simply isn't reliable enough and frequently there are unforeseen consequences if it does work, but many times for what ever reason it doesn't work, broken restore points, etc. and for me that just isn't good enough, so I went for disk imaging for my replacement of system restore.
Another issue is that many people think it is much more than it is (the name doesn't help), it isn't a back-up application as many think.