I built the 4*60 and the Ultra Sport 60

The 4*60 builds slightly easier than the US60 and more suitable for a beginner builder.
As for flying the US60 is by far better, smooth and advanced airplane, the 4*60 is wonderful first low wing airplane flying slow and takes hard pulls really easy.

I built the 4*60 before the US60 looking back I wouldn't build another 4*60 I graduated from it, as for US60 I just ordered another US60 kit.
The US60 is not that much more work it seems the US60 took less time for me than the 4*60, just need to pay attention to details like the wing incidence because at the end the US60 is much more advanced airplane.
I'de go with the US60.

Alex