Of course, Nokia 808 has better camera(41mp vs 13.1mp)
But overall, Xperia Z is the best, bigger and full HD screen, water and dust proof, alot slimmer, supports 4g lte, 2 gb ram compared to 512mb of nokia 808, quad-core 1.5ghz on xperia z compared to single core 1.3ghz on nokia 808,supports all latest software by android etc!
Nokia 808 only has better camera, nothing else!
Now it's up to you!
If you could increase your budget, you could get a Nokia Lumia 1020, it also has 41mp camera 