My iPhone fit snugly into the Catalyst Waterproof without a hitch. All features of my iPhone, including Touch ID worked perfectly, though it is recommended that you rescan your fingerprint with the iPhone in the case to get an exact image. In terms of operating my iPhone, the only small adjustment was having to press down on the screen a little bit harder than I normally would for it to register. Make sure you push the iPhone right down into the case to make sure there's good contact between your iPhone's screen and the case screen.
As with last year's review, the Catalyst Waterproof comes with strict instructions for testing the case before submerging it in water. However, things have been simplified significantly. There's still an O-ring that is essentially the waterproof seal for the case. You need to make sure this ring is sitting properly within the case and that it is not twisted in any way. Catalyst provides full instructions on its website. Aside from that and making sure the charger port / audio jack plug is closed, you're good to go. I performed Catalyst's recommended test and found no water penetration into the case. If your iPhone was to go for an unexpected swim, the Catalyst Waterproof case will make sure not a drop gets in.
In terms of protection from knocks and drops, the Catalyst Waterproof provides excellent, all round protection. If your iPhone was to take a tumble, knock or drop, you can rest assured that the case provides significant protection.
The Catalyst Waterproof's slimmer form-factor and easier operation makes it a solid option for those who want a high level of protection for their iPhone with the least amount of additional bulk. For everyday protection -- or even specific occasions where you know your iPhone will be at particular risk of damage -- the Catalyst Waterproof is definitely worth considering.