I did not find the phone slippery. It is very thin whereby the size of it actually for me makes it easy to handle. Now the iPod touch 5 I had was so thin and small I had to get rid of it.
The camera is a lower priority to me. Performance, comfortability, the screen and audio all come in far ahead.
If those are your priority.......then you will love the M8. It feels great in your hand. Built from premium materials. Has a great screen and is extremely fast and the battery life is awesome. The sound quality is well known......but the camera is good...but just not upto part with today's standard smartphones.