I have a Canon 200DG bag and a Tenba Pro 2 photo insert.
The 200DG is for when I know I'll be taking photos. I can easily fit two camera bodies, four lenses, gaff tape, flashlight, film, charger, USB cable, blower, four cleaning cloths, a huge packet of silica gel, a 77mm filter, and two 52mm filters all in one bag. This is without having any lenses attached to a camera body, though. If I kept a body and lens attached then it would probably hold one less lens. I didn't buy it because it was made by Canon. I found a website called cambags.com and did a comparison. It was the perfect size for what I do. The fact that it's also very reasonably priced is just a bonus. I've been using it for months now without any problems.
The Tenba Pro 2 has a permanent spot in my messenger bag. I can go about my daily business and always have my camera with me without lugging around a dedicated bag. Until recently it held two camera bodies and two lenses. Now I keep a single body with lens attached for when I need quick access to it. It sits comfortably on its side. The other two compartments contain a second lens and a lens hood/lens caps/cleaning cloths. I bought this after reading a recommendation by a TPF member. It's padded enough that I don't worry about my equipment being damaged. It's small enough that I can still keep a laptop and books alongside.
The bag you linked to looks a bit snug. Is it possible to fit the camera and lens in on its side? That's what I do with my Tenba. The left side of the camera touches the bottom of the bag and the right side (with the grip) faces upwards so it's possible to grab it quickly. If that's not an option then I can't see the harm of setting the camera down on its screen.