It's a completely different arrangement for the camera. Here are some points: 1. There's supposedly a space/weight saving by not having to have a mirror and pe

It's a completely different arrangement for the camera. Here are some points: 1. There's supposedly a space/weight saving by not having to have a mirror and pentaprism to give you a viewfinder. Unfortunately, this space/weight saving seems to mostly have been negated by the tendency to make the lenses bigger and heavier. 2. The viewfinder is electronic, not real. This may take some getting used to. It may also be less practical in some situations and more practical in others. Consider when there's loads of light around (you're wearing sunglasses and the electronic viewfinder is too dim) or when it's really dark (the DSLR viewfinder is too dark). I'm told that the electronic viewfinders these days are really good, but I'm sure it's a matter of preference. 3. There's no mirror that flips up, which can reduce camera shake. You can even get most of the mirrorless cameras to use a fully-electronic shutter, so taking a picture can shake-less and silent. 4. The lens mount is closer to the sensor, which can make it easier to make some lenses (mostly ultra-wide angle lenses). 5. The focusing system is usually way better. DSLRs depend on a translucent part of the mirror to direct some light onto a focusing sensor. Mirrorless cameras have a load of split pixels scattered across the main sensor, that allow them to do phase-shift focusing. But because they're using the main sensor, they can do things like work out where people's faces (or even eyes) are, and focus on that. 6. The battery usually doesn't last as long as with a DSLR. For example, I went out one night and took 1758 photos on a single battery on my DSLR. You'd need more than one battery on a mirrorless camera to do that.