I've had the DC500, 600, & 800. The 800's larger battery is very nice, although I did find some larger batteries than SeaLife's for the 600. I am very disappointed the 800 seems to have focus problems - the outer edges of the pictures won't focus. I did three dives on my first 800, then had it replaced. Have done one dive on the replacement 800 (SeaLife has always had great customer service by the way), and that appears to have the same problem. Very disappointing. Not sure what I am going to do now; waiting to hear from SeaLife. I can't believe I'm doing anything wrong. Have sold my 600, so I am kind of stuck for the time being.