What are the pros and cons of a Pentax camera versus an Olympus one?

Olympus:

Pros

- small and lightweight, but well built

- very good optics

- thanks to short registration distance, virtually any SLR lens is usable, with limitations such as loss of AF and aperture control

- good in-camera JPEG processing

- Excellent in-body stabilization and sensor cleaning

- Excellent quality lenses

- Good live view implementation

Cons

- small and lightweight (some don't like that)

- ageing 3-point AF system for their consumer DSLRs

- small viewfinder

- very expensive lenses and limited line-up

- difficult to achieve wide-angle coverage

- noisy sensors at higher ISOs (due to smaller sensor size)

- heavy noise reduction algorithms mean loss of detail even at lower ISOs

PENTAX:

Pros

- solid, well-built bodies

- Excellent ergonomics

- weather sealing for all their current line-up

- compatible with over 24 million lenses that Pentax has produced over time, stretching back to the 60s.

- supports the open-standard Adobe DNG RAW file format, as well as PENTAX PEF

- good in-body IS and sensor cleaning (not as good as Olympus, though)

- line-up of Excellent quality lenses, including the acclaimed Limited lenses

- lenses cheaper than competition (but often better in image quality and build)

- APS-C size sensor means cleaner images at higher ISOs

- 11-point AF system featuring 9 cross-type sensors and accurate AF

Cons

- relatively small lens line-up and availability (but better than Olympus)

- AF slower than competition in low light (but more accurate)

- slow continuous shooting performance

- quirky menus on older models

- bulkier and heavier models

- entry-level models work with AA or CR-V3 batteries (some don't like that)