Here's a nice comparison article of several bridge cameras.
http://www.imaging-resource.com/PRODS/best-superzoom-2014/best-superzoom-2014-A.HTM
After going through it all, the P600 was the winner. But if I had my druthers, I think I'd go for the Fujifilm S1. It's performance was very close to the P600 (according to the article) and it's weather sealed, But big difference maker for me would be how fast the buffer clears. I have a bridge camera now that takes upwards of 30 seconds to clear just 5 full frame shots, and I detest that feature. If you're birding or doing other wildlife shots, waiting for half a minute for your camera to swallow a burst of photos always leads to missed shots that may have been better than what you already catured. Not to mention blood pressure elevating frustration! lol. Knowing that it takes a long time for the P600 to clear its buffer is a big negative for me.
I think if I had to choose between the two, it would be the S1 I'd go for. .