Based on the response so far, it seems that integrated bar-stems are "less preferred" to put it politely. Yet the bicycle industry is designing many of their high end road bikes with these "devices" . And we are buying them (myself included) .

In my particular case, I chose the bike I wanted... and it happened to come with an integrated bar-stem. It's working out well, so I'm keeping the setup as-is. However, if it didn't work out well I would have been out of pocket for the original purchase plus whatever the replacement solution would have cost. I don't see how this is an advantage for the customer.