End of the day is still up to individual preference.
My view, never hear before doesn't meant no good.
Just like on the road. U still see so many different brand of cars.
Last time people say korean car no good, but look at the market now?
Another factor is costing.
Pentax costing and...
55-300, im using it.
In terms of pic quality i think is okay.
But u need stable hands when using the full focal length of 300mm..
I will rank pic quality in the followingsequence
3,1,2.
Just my humble noob opinion