Originally posted by TG10 can be cheaper
Nope, owning a Canon or Nikon system is more expensive than oweing a Pentax system.
Here are the key qualities of the brand:
1-weather-sealed bodies for DSLR and water-proof compact cameras : Pentax can be efficiently marketed for people who love being outdoors. No other brand offers you so many lenses and bodies that can be used in the rain, snow, on the beach, without worries that the equipment will be damaged. Pentax is the only brand offering entry-level weather-resistant lenses
2-Ergonomics : the Pentax DSLR bodies are designed to TAKE PICTURES. When you read a Canon Rebel review, the reviewer always comments that after some time, the body gets uncomfortable to use. Pentax bodies are fantastic : buttons are well placed, you have access to most features intuitively, there are clever shooting modes not found on other bodies from other brands. The viewfinders are also generally better.
3-SR : called Image stabilisation by other brands. In short, with Canon or Nikon you have to purchase lenses that are optically stabilised, and these cost more, plus some lenses are just not available with image stabilisation. With Pentax, the stabilisation is in the body, so EVERY lens gets stabilised.
4-Older lenses : every lens ever manufactured for Pentax still works with Pentax bodies. No other brand offers this. It means if you have (or find, at a garage sale or anything) an old Pentax lens, you can still use it. This means you have access to inexpensive but fantastic lenses.
5-Limited lenses : these are often regarded as the best lenses ever manufactured. They are ludicrously small (a small Pentax DSLR body with a DA limited lens is smaller than some point-and-shoot cameras). They are optically amazing. They are expensive but not overly so.
5-Coatings : Pentax is recognised as the leader in optical coatings, other brands try to emulate the Pentax coatings. These improve the optical qualities of a lens.
6-General lenses qualities : there are no "bad" lenses in the current Pentax lineup. Even the inexpensive "kit lens" that every brand has is better with Pentax. The Canon and Nikon kit lenses make excellent doorstop (I'm barely exaggerating).
7-Regarding compact P&S, most brands are interchangeable, but like I said earlier Pentax has a great line of water/snow/dust/cold/shocks resistant compacts that perform very well while still being compact (the latter cannot be said of the Canon D10 competitor).