Besides the start-up time and stylus, it is hard to find fault with the FX520. Image quality has also improved and we really like the features that are incorporated with the touchscreen.
Being waterproof up to 40m and with access to all of the FS5 or FS3's functionality, the MCFS5 marine case is perfect for the regular scuba diver or snorkeller. If you can afford it, that is.