As an occasional poster only popping in with a small window of time, I derived the following impressions, and will only elaborate if requested. Ironically, the story I ultimately lean towards is the one that I have least interest in as a premise. Still, they're all solid concepts, and I've always had a bit of a bias towards the fantasy option.

The first tale strikes me as the one with the strongest grasp on pacing, length, and the dynamic of internal thought mixed with action. It's an easy trap to fall into 'word soup', where the tale is somewhat compromised by too many extra sentences put into it that somewhat mute the action. I observed little of any of these things, and I believe as a result the first tale is the best written, and thus earning my vote. I also enjoy the proper spacing, as a true story really doesn't need to be expressed in homogenous paragraphs; some 'breathing room' is a good thing. Short, but quaint, and the other stories were hardly much longer, only carry the appearance of said length.

This is not to say the other two were bad, but I do believe they were flawed in some of the ways I mention above. 

The Amulet of Friall is ultimately a good contender, but what gets me is the pacing. Nothing stands out more than the plot twist, revealed rather anticlimactically in the middle of a paragraph-blurb through "Estelle grinned too and attacked Hazel with her magic. Confused Hazel looked up." All without spacing or any sort of breathing room. I didn't get anything from this - instead, I read over it, went 'wait what', went over it again, and I have to say, it is perhaps the clunkiest point in the story, particularly with the almost detached, vague deadpanning of 'and then she attacked her' and the next sentence being a very flat expression of confusion. I'm not someone who's all about "show show show don't tell show!", but this is a case where I think some serious attention to the idea of actually showing it happen instead of telling would have made an impact. As it stands, there was none. My reaction was identical to Hazel, ironic considering the significance of having your partner in a secretive organization tell you 'lol nope I was bad all along'. There was an effort to foreshadow later on, but for how little impact it made to the characters, it strikes me as a bit thrown in and insignificant. The pacing from there on left me going 'woah, what's this now'. I think the section could have seriously benefited from spacing and more expression of the characters. The plot is sound, yet the execution leaves a great deal to be desired.

And again, though this is an issue with both stories, there is nothing wrong with some spacing and partitioning things out. I believe  Calle's work is an excellent example of how to do this. It makes things easier to read, and if it became habit, I think it would be less likely to encounter points like the above. Do not take this as a condemnation of the work; I'm simply good at going on and on about what I think is wrong, despite ultimately enjoying the work for the most part.

The third story is written in a way that's not far off from my own when I get into tales. Thus, I can relate to it automatically, as well as spot some of the persistent flaws. It seems to me that the tale could have used a bit of trimming; less sentences to convey the same concepts, or less elaboration when the original piece would have sufficed. This is a vague judgement that would take opening a can of worms I don't currently have at the moment, although if those particulars are desired, I'll give an effort to working them in down the road - for now, I'd just like to get the impressions out. Obviously I suffer from that too, and without good proofreading I'm obviously going to look a tad hypocritical when speaking of it. And again, spacing is good. Varied paragraph lengths is entirely natural and even desired.

There's points here and there that could have used a bit of review to catch. From the first, I couldn't actually spot anything on a quick glance, though I imagine it's there and reviewers with more time and a deeper view will be able to point out little things. From the second, a sentence stood out as very abrupt in the middle of the action, "Two men entered through a door". From the third, "he leapt over the fifth story railing and aimed his body straight downwards like diver,". Very minor, nitpicky things.

Seeya again in 3 months.