I'm very much preferring the vertical orientation. It took a while for it to sink in when Vektor
first presented it, but it's really distinctive.
has a pretty extensive entry about his work on this at his blog here: http://vektorvisual.com/blog/
I have a couple of those sparking rayguns - they still sell them. That particular model/mold has probably been knocked off twenty times by various manufacturers...they come from China these days.