I've owned and flown a lot of 50CC Yaks. I love them. I've had 2 EF 50CC Yaks, Aeroworks 50 CC Yak, TOC Yak, I've also owned the Pilot RC Sbach 50CC. The EF Yaks are 18lbs and the Aeroworks was even heavier. The Sback was right at 16lbs. I love the weight but it is considerably smaller in comparison.
The Sback CLEARLY does better flat spins and waterfalls. The Yaks do better at KE and hovers. The Yaks also harrier better but only slightly. I gave my Sback away to a friend and kept the Yaks. I think overall the Yaks are a better flying airplane. At least I like them better.

I've also had Edges and Extras and I like the Yaks better than them also. But the Sbach is a sweek plane and was exactly as advertised. It is amazing at how comlete the ARF is. The fuel tank was plumbed and installed. All the hinges are done for you. The cowl has a ring and is pre installed. the rudder cables are installed, and it's a high quality ARF. The Yaks are high quality but not nearly so complete.

I'd still get the Yak. I like them that much better.
Thanks
Barry