Pentax dslr upgrade?

Hi everyone this is typed on my iPhone, any way I have a Pentax k-m I want to upgrade to k-5 do you think that is good? I'm struggling because I was thinking to move brands to canon or Nikon because you can get them anywhere with competive prices.
The big thing I need help with is if I upgrade from k-m to k-5 there's a clear difference in spec like I'm moving up the ladder
Now if I get a canon or Nikon from Argos or currys and so is it a step up or just a side step because they go from £550-650-700 with no real clear difference that I can identify? But if you go to a pro shop an entry is starting at £800 with models.

If megapixels are important to you, I think the jump from the K-M to the K-5 is worth the jump. Also, how much have you invested in Pentax gear, such as lenses? If you want to switch brands, that's something you have to think about.

But I'll run through the benefits of upgrading to the K-5:
1. More megapixels (assuming this is an important attribute)
2. A slightly bigger sensor size. K-M sensor size is 23.5X15.7 CCD Sensor, but the K-5 has a 23.7x15.7 CMOS Sensor.
3. Slightly bigger LCD screen
4. Weather sealed
5.Max ISO: 51200 (but does not perform well at high ISO's)
6. HD video capabilities
7.SD/SDHC/SDXC compatible

If you want to stay with Pentax, I'd go for the K-5.

The K5 is a fantastic camera and the part that really impresses me is the fantastic low light capability. It has low noise and an incredible ISO range. It can see in the dark better that I can.

This camera is amazing for sports in poorly lit arenas and halls.

The rest of it is good, and the autofocus is better for sports.

Here are some samples and
http://aviewfinderdarkly.com.au/2011/04/14/pentax-k-5-for-indoor-sports/

http://www.tasmanianpacingclub.com/images/Special%20Athletes/specialathletesaug2011.htm

Here's the catch. Whatever camera you use, you get the same picture. It's you that dictates picture quality. The camera is only a tool. You only change your tool, the camera, if you find it is limited in something you really need. It's like if you need to shoot more in low light and you can't survive with a maximum of ISO 1600 then you get another camera.

Yes, the advantage of Canon and Nikon is their popularity making them very much available everywhere you go. The advantage of Pentax is the other way around. Your camera, as with all other Pentax dSLR's, is completely compatible with old K-mount film lenses. The best part? It's also compatible with all screwmount or M42 lenses with the use of a cheap adapter. All of these lenses, K-mount or M42 are not limited to the Pentax brand. Any will do from the highly desirable Voigtlander and Zeiss to virtual unknowns like Vernon Edonar and Polar.

I'd stick with Pentax. No use switching to another brand if you already have k-mount lenses.

An upgrade in the body depends on your needs. Do you need the extra mega-pixel for cropping or enlargements, slightly lower noise when shooting high ISO, and higher frame per second rate?

If you answer no, then don't worry about it.

Of course, if you can afford it, then why not. We all like new toys.

Keerok is right, there's more lenses available for Pentax than any other camera brand. A side hobby of mine is adapting older lenses to my digital bodies, and many of them are Pentax K-mounts and screwmounts. One is a Pentax 50mm SMC Takumar that's become a workhorse lens I use more than the Canon one. It's that good.