I have no words for TrialHead that was launched in dreamforce last year .I experimented using TrialHead for lightning module last week and I must say worth spending time on TrialHead .
I am very new to Lightning and I had read Release notes and Lightning developer guide but somehow I was not so confident .I must say once I have completed challenges on the TrialHead for these modules my confidence level has gone up.No more I feel that I dont know basics since I have coded the assignments asked and have passed all those to earn badeges.
I am thankful to creators of this tool and this has made learning real fun .The great team at salesforce Sandeep ,josh or Chris Duarte are really helpful .I have reached them no of times on twitter if i find any difficulty related to any problem in Trailhead and they have been super helpful .
Thanks TrailHead and I have requested for more lightning related tutorials on this . Please note Trailhead is free of cost and your best tutor.