I would tend to agree with you Jock. Olympus has by far the best housings coming from any major camera maker but the differences between these two housing is significant. To compare apples to apples you need to at least add a port and
gear for the lens. Olympus has chosen to sell a port for the 14-42mm "kit" zoom. A much better choice would be the 12-50mm "kit" zoom which is being supported by Nauticam but at a greater cost for a port and gear that will allow use of the full zoom range plus the macro switch feature.
Cost wise in the us the Nautican NA-EM5 housing, 14-42 port and gear for the 14-42/9-18mm lenses is now listed at around $$1800.00.
The Olympus PT-E08 housing, port for the 14-42 and 14-42/9-18 gear are listed at $1448.00 you will need to add another $50.00 for the port adapter for the 67mm closeup lenses which is built into the Nauticam port bring the total to $1498.00.
The Olympus tray is also higher than the much better Nauticam tray as well.
The upsides to the Olympus housing will be for those moving from the 4/3 DSLR systems to the M43 E-M5 housing if they want to use their 4/3 lenses and DSLR system ports with the Olympus adapter. In the Alex Mustard review of the Olympus housing for Wetpixel and UWPMAG.com you will see the Olympus macro port for the 50mm macro DSLR lens and the 170mm dome port for the Olympus 8mm fisheye, 7-14 zoom, 9-18, 11-22 and other DSLR lenses. Those that already own these ports and the ones from Athena, Inon and others may stick with those ports and lenses.
Let me finish by saying yes I teach workshops for Nauticam and yes I have used Olympus 4/3 and M43 equipment for years.
Phil Rudin