Well, in that case I may just have to sell the 28-300 f/3.5-5.6 and put the money towards the DA 300

It comes with a nice quality and rubber fronted hood and I think the lens works well against flare. I haven't read anyone complaining about flare either. You'll get a huge boost in image quality over the 28-300, I know it without even trying that lens out.
Yeah, that 300/2.8 would be nice for my sports shooting but as you say, it's too much money for it.

I think after a Panagor 90mm f/2.8 that is my next lens to get! I think it would really work well to replace my Sigma 28-300mm. I was thinking about the Sigma 300mm f/2.8 but.. At $3400.00 hardly seems worth it. How is the flare with the Pentax, or does the hood take care of alot of that? (hopefully it comes with a hood I have only seen photos of it without the hood)

What's it like? Pro quality glass.

Is it worth the money? Yes, if you can afford it. I got my copy at a crazy Amazon.co.uk blow-out sale. At least lenses are much cheaper for you on the other side of the sea. Second hand is no problem in my eyes, SDM issues seems very rare for this lens.

How is the IQ, focus, weight? IQ is really good. The times I get a blurry and bad shot and blame the lens always backfires when I get super sharp shots and realizes that I'm the limiting factor, not the lens. It's so sharp it has proven to be extremely useful both on the Pentax Q and works well with teleconverters (in MF).
I have no focus issues with the lens and it's probably the fastest SDM focus in the Pentax line-up.
Weight is very subjective and as it's even lighter than my sports workhorse Sigma 70-200/2.8 HSM II. Great IQ per weight ratio!

It's in my bag every time it's possible to take it and often I end up shooting mostly with that lens. I'm a tele guy as you can tell!

You said you have the DA 300mm, I am curious, what is it like? Is it worth the nearly $1400 (or would a second hand one be better due to a lower price or is it something you would only want new?)
How is the IQ, focus, weight?