Hi Mark,
I bought a 6" F8 Acro recently s/h from the classifieds here after wanting one for many years. I was quite surprised at how well it performed on the planets. Yes, there is some blue fringing so I bought a baader semi apo filter which I think is actually a combination of the two filters you mentioned. It helps a little but honestly, I usually end up taking it back out. At 100x plus, I found the combination of the filter and stopping the lens down to 4" gave very sharp and contrasty views albeit somewhat dimmer. Stopping the lens down seems to me to be equivalent to what the semi apo filter does - I don't think I'd buy one again. (filter, that is).
One thing to keep in mind with a 6" F8 acro - being relatively long, it feels the wind and there have been nights I've had to switch back to the 4" refractor as the 6" was wobbling about too much.
A plus with the scope is that you can take the focusser out and replace with a low profile focusser and get a binoviewer to focus with a 1 1/4" diagonal or you can take the step-down adapter off and make up your own and screw the low profile crayford onto that and use a 2" diagonal and binoviewer with a bit of back focus to spare. No angle grinding required.
I paid less than $500 for mine and think it's the best bang for buck scope I've ever had. Certainly not as bright as an 8" reflector but I prefer the images in a refractor.
I built up a wooden alt az mount and printed some setting circles for it - using sky safari on the ipad, I can usually find stuff pretty quickly.