So doing some more research the QHY-5 and Orion Starshoot are the exact same thing so I guess as far as that goes cheaper it is (unless anyone can give me a compelling reason to spend the extra - and I know about lack of cables).
Bassnut - the ED80 would be to replace the 12" (just a smaller widefield scope) not to mount on it as a guider. Thats why I want the OAG, so the setup will basically be 12", OAG and DSLR (i.e - no different in weight to what I have currently). If I do use a seperate guide scope on the 12" I was thinking of just modifying the current finder.
Multiweb - how come you don't use the OAG on the 5" and what do you think of the cheap meade OAG?
On the guider (and it appears that all agree the QHy-5 and Starshoot are great) what about Robbies suggestion about going to a camera. I discounted things like webcams etc. due to resolution and sensitivity but if you could get another camera (given I said budget was ~$500) like the DSI II (for $600) would that be a much better option (gives some extra felxibility to image planets maybe)?
Thanks for the comments so far - keep em comming