The start-up time (as noted everywhere) is a little slow compared to most DSLRs but I found that the large power switch is perfectly located near your thumb. As you pick up the camera with your right hand, it is very easy to flick the power switch on with your thumb, saving you a few moments and by the time you have the camera is in a shooting position it should be ready to shoot.
When holding the camera at ground level, the flip-up screen is a huge bonus. I tended to hold the camera like a joystick and used my thumb over the top of the camera to trigger the shutter.
When I was carrying the NEX-5 & 18-55 lens around (not shooting), I found that gripping the lens was the most secure and comfortable way. I also found that it would fit snugly into the pocket of my shorts and very easily into a jacket pocket. It is still a very pocketable camera even with the 18-55 zoom! Obviously, it won’t fit into your jeans pocket but I’d never put a camera there anyway.