I personally use the Xtreme brushes (current favourite the Xtreme Soft Hybrid) as I like the weight and speed they impart to your work. They do not have the ultimate scrubbing power of a denser bigger brush such as the Super-Lite, but for me the weight is more important.
I never have to get another brush on the pole as even if I encounter birds mess, bee spots or spider's nest's I wet, scrub, soak and then walkway and come back for a 2nd scrub. This is usually all that I find is needed even with an Xtreme. I do now have the Super-Scraper fitted to my poles so this is even easier, quick rinse and a scrub with the abrasive pad takes care of anything and lets you get back to standard cleaning with the brush.
For some scrubbing power and bristle density is more important - the larger Super-Lite are better suited in this case. It really does depend on priorities and often working method used.
Pure H2O - I am working with a Super-Lite brush at the moment that only weighs 175g so not as light as the Xtreme, but a good bit lighter than a standard Super-Lite. I still prefer the lighter weight of the Xtreme, but this could be the halfway house that suits another section of people.