f5 or f8?
There are some reviews here:
http://www.cloudynights.com/page/art...mm-refractors/
The general consensus seems to be that the f5 has a fair bit of CA, and so a number of people use a minus-violet filter for planetary viewing with these.
I think you will find that Skywatcher, Synta, Celestron, etc. are all re-badged from the same factory.
All the best,
Dean