Casio released their first underwater camera just after our last muster. Joining them as new additions to our muster this year are Sony and Samsung. In addition to watproof ratings, most lines now sport shockproof and freezeproof ratings as well (so-called "rugged" cameras). The exception in our list to ruggedness is the Samsung AQ100 which is merely waterproof.
Casio Exilim EX-G1
The Exilim EX-G1 is the oldest camera in this group, having been announced just after last year's muster. The EX-G1 has noticeable, but not horrible, geometric distortion at the ends of its 38-114mm (equivalent, 3x) zoom range and general softness in its output. It was, when it was released, the first ultra-slim rugged camera but now there are better (albeit pricier) options. The EX-G1 is waterproof to 3m.
Fujifilm FinePix XP10
Fujifilm's first attempt at a waterproof camera got a mixed review from the critics—many people liked the style, but not the photos.
Olympus Stylus Tough 8010/6020
Since branding the "Tough" derivation of the Stylus line, Olympus has focused on keeping these cameras as the most rugged of the mass-market compact cameras. They are waterproof down to 10m, freezeproof down to -10°C, and designed to survive a 2m fall. Despite the rugged specs, the Olympus Stylus cameras have tended to produce mediocre output and can have tendencies of being slow, even for a compact camera.
Panasonic Lumix TS2/Panasonic Lumix TS10
The TS2 is Panasonic's second generation; the two cameras have slightly different zoom ranges but otherwise the TS10 is a down-spec version of the TS2. The TS2 is waterproof to 10m vs. the TS10's 3m.
Pentax Optio W90
The Optio W line has had problems with noise in the past, and have never had stabilization features to help reduce the need for higher ISO. The Optio W90 does pretty well up to ISO 400, and the Optio W90 has significantly improved shutter lag since earlier models. The Optio W90 is waterproof to 6m (20ft) and has a 28mm-140mm (equivalent) zoom range.
Samsung AQ100
First off, the Samsung AQ100 is not a "rugged" camera in that it is neither shockproof nor freezeproof, merely waterproof (3m). The Samsung AQ100 is the lightest camera in the group, and just misses being the smallest. It does however have the longest zoom range (36-180mm equivalent).
Sony Cyber-shot DSC-TX5
The Sony Cyber-shot DSC-TX5 is the smallest camera in the muster, yet it is rugged 10MP with a useful wide zoom from 25mm (equivalent) to 100mm. It is only waterproof down to 3m, and most of the controls for the camera (besides the shutter release) are done on a touch screen which can be difficult to operate under water.