I remember mentioning this before, too lazy to look back though. Reading Fairytail is good bcuz it allows those unexpected moments to really hit, the anime gives you too much time to prepare for it.
I will say this though, certain episodes in the anime must be seen after reading, just bcuz the shows addition of magical circles help with the impact it has on the fans. Example being when Mirajane remembers what happened to Lisanna, and her resulting battle. Really well done in the anime, imo.
Another thought on anime/manga differences. The big one is speed, some prefer going at their own pace, others prefer the speed of the anime. I personally prefer reading manga, so I can fast forward the dragged out scenes in the anime, watch the fun and epic parts. The only part I'm waiting on in FairyTail is when Gajeel goes all fucking Shadow Metal Rape Mode.
Just me, I can watch short anime without reading it's equivalent, anything less than 50 episodes. If I find it interesting enough, I'll go looking for a continuation, otherwise I end up reading it. I started reading Attack on Titan, I like it the same way I like Game of Thrones. I don't find it addicting, or all too fascinating, the 'fucked up' parts are just a matter of experience imo, one could get used to seeing immoral concepts, leading to a more critical view. I like it bcuz of other details that matches with the story well. Game of Thrones has got to be one of the funniest shows I've ever seen, anyone that's seen or read the series would know. Attack on Titan, brings a lot of perspective that I can respect, human nature and all. Only reason why I was hesitant with Attack o Titan when first heard of it near the beginning of the year was because I didn't want to get caught up too fast. I'm around the part where the new recruits join the scout legion.