Originally Posted by PentHassyKon 
Just to follow-up since I started this thread-
Bought the 50-200 initially and not long after an opportunity for a 55-300 came up. Needless to say I now have them both
Will do some comparison shots soon......
Would still be interested in a fast 200 - still lusting for that 200 2.5.
.....
OR maybe a 300 2.8, 400 5.6?
Hold out for that K 200/2.5. It will be worth the wait. Hope you don't have to wait the 20 years or so I did.
There is just no substitute for speed in the conditions you want to shoot.
I have the K 300/4 as well as the M 400/5.6. I have used the K300/4 with some success in dimly lit school gyms. This lens gets dumped on by some but I submit it is the best bang for the buck in the 300mm manual focus category. Forget the M 400/5.6 as it is just too slow and big for that application. Fine for outdoor work where you have lots of light and room but IMO hopeless in an auditorium.
Tom G