First, if you finished the tutorial, I am very interested to know that you did. I am also interested in how long it took you (in hours). Please drop me a quick email at white.eric at microsoft.com.
In the end, I believe that programming in the FP style is useful and powerful. When programming, it enables you to focus more on the problem domain, and focus less on the plumbing.
I think that in some circumstances, imperative code is more readable than FP code, so I am not (yet) an advocate of doing everything only in the FP style.
And as always, as my learning evolves, I’ll certainly expose my learning process publically.