RE: Synergy 90 ARF
One thing I would say about this plane regarding F3a use is that it is a bit more complex to set up due I am sure to its very large surfaces. You need some quite accurate powerful servos and a reasonable amount of exponential to get it "turned down" and smooth but once you have done this I reckon it's pretty good.
Also useful is a coarser pitch prop than you would fit for 3D, so that the power "flows" more smoothly and you don't get the more dramatic speed differentials with different power settings such as you do with the finer pitch props.