It's up to you. I've made four levels - of variable quality but none awful, judging by the ratings - so it's doable.
I find the tools easy once you get the hang of them - but clearly if you want to build anything decent you're going to either put in some serious 'trial and error' time and skip the tutorials, or sit through them and go from there.
There are over 1 million user levels now, so it would see a fair percentage of LBP owners create, but not the majority - so maybe the game for you is better played rather than created.
Try to be reasonable... its easier than you think...