SO much of this depends upon the room that it is apparently not helpful for us to speculate. Obviously, people have had success with both approaches.
I like Doug's approach (not "either or" but "both and"). "Less" is not "More", More is More!
I have not had any trouble with the omnimount thing. I have an old Mitsubishi CRT RPTV, so the weight is absolutely not an issue for me. Again - for me, in my room - I preferred above to below acoustically (though not aesthetically). As you can see from the other responses, the room seems to make even more difference than placement on this topic. I do not think that using the omnimount shelf for a VP150 would be a problem; it is quite wide. I put those little vinyl bumper stickons on the bottom of the speaker and shoved a wedge under the back.
It'll be swell.
bibere usque ad hilaritatem