"The current versions of the tiles actually have a two percent loss on efficiency, so 98 percent of what you’d normally get from a traditional solar panel, according to Elon Musk. But the company is working with 3M on improved coatings that have the potential to possibly go above normal efficiency, since it could trap the light within, leading to it bouncing around and resulting in less energy loss overall before it’s fully diffused."

Which suggests that on a square footage basis it is similar. The difference being that on a manufactured panel the cells are all exactly next to each other with no seams, and with the Tesla roof they appear to have a moat around them that varies a bit with roof tile style.

That said, assuming you cover your entire roof which will include both "ideal" south facing (or north facing in the southern hemisphere) and "non-ideal" north facing parts of the roof you may get enough additional generation from the extra tiles to push it over a more 'traditional' solar install.To be honest I'm thinking about replacing my perfectly fine (if nearly 15 year old) solar panel set up with those roof tiles. That and a couple of power walls and I just might be able to go 'gas only' with PG&E.