I was decently satisfied with my Panasonic waterproof camera, which was the previous generation from the current TS30 model. If you just want to snap some photos underwater or just have a camera you don't care about getting wet, this may be the way to go.
The Olympus TG-4 looks like it's on a whole other level though. The lens they put in that Olympus is so bright. If you care about picture quality and the ability to use it for more than just water snapshots, find a way to get this camera.
In the end though, make sure to follow all the recommendations in the manual about caring for the camera. There isn't a single waterproof camera out there without a reviewer saying the camera died on them due to faulty seals, but I think a lot of these people ignored the steps you have to take when using these cameras.
Rinse the camera off with clean water after using it out in the wild. Let it dry completely before opening the memory card/battery compartment. Make sure the seals and edges of the door are clean whenever you open/close the compartment. My Panasonic has lasted 4 years and many beach/pool/river trips without any issues while observing these cautions. The main thing is letting it dry completely - I would usually let it dry for a minimum of 48 hours before opening it up to get the memory card out.