Everybody's different, but most people find the 4* to be an easy build. Another nice thing about the plane is that the design is very forgiving. That is, you can make lots of mistakes, and it will still fly fine.

The GP P-51 is (IMHO) an even better build. It is not easier, and it does use more advanced building techniques, but I really like GP's engineering. Learn all you can on the 4*, and you will LOVE the GP P-51.