Doing "research" on speakers is totallyy worthless unless the reesearch includes actually listening. Buying speakers based on reviews or someone's opinion, is like letting someone else choose your mail order bride. The chances are very small that you'll get something that satisfies you.

My advice: Don't buy any speaker you haven't heard and liked.

Living in NYC you have a multitude of places to go and audition speakers. Make the effort!

Probably not in a store near you either, but for the price ($349 pr) I was impressed by the  Music Hall Marimba speakers I heard at RMAF this year. They were also conveniently mini reviewed in the latest December issue of Stereophile.

 I am very familiar with older (2008) Epos speakers, but have not really listened, except briefly, to the Epic line. I have heard many Polk speakers, but mostly LSi7 and LSi9, and I spent about 20 minutes with a pair of the new Polk LSiM towers at RMAF.  I'm currently using Epos M12.2 stand mount (bookshelf) speakers in the main system, and Polk RM3000 satellite /passive sub speaker system in the TV room. Oh, and Polk weatherized outdoor speakers on the patio. Based on this background, I prefer the sound of the Epos speakers I have heard over the Polks mostly because the Epos has  leaner upper bass, though the Polk's high frequencies were smoother and a bit mellower in comparison. But I have not heard the actual speaker models you listed, so all this information is really worthless.

PSB Image line, Klipsch RB RF, NHT, Wharfedale Diamond, Monitor Audio, Focal, and others each make several speakers that could fit your price and size range, and they all sound good to many people or they . If I were forced to go out and buy a reasonable (to me) stand mount speaker right now for myself, I would have to consider the B&W CM5, or KEF LS50, Both around $1,500, both reviewed recently in Stereophile, and both of which I heard at RMAF.  I have yet to hear the newish Epos Elan's, but I would certainly like to hear them before making any decisions.

I could go on. I don't know if this helps answer any of your questions, and I don't really see how it could because there are so many possibilities. JoeE SP9 is right because research can indicate an excellent speaker, but it could still sound like garbage if it's not what you like. Even then it's tricky, for instance, I tend to like the sound of a lot of speakers I hear, until I hear them directly compared to something else.

Lastly, with 15 watts from your receiver, I would probably keep an eye on the efficiency ratings so as to not get the most inefficient speakers.  And please don't put bookshelf speakers on a bookshelf unless they were specifically designed for it. They usuall sound better at least 8" or so from the wall, out in free space a bit.

I'll bet after listening to some speakers my point about buying what you've heard and liked makes a lot of sense. I'm glad to hear you found something you like.

What Demondog said about speaker positioning is correct. Poor positioning can make even the best speakers sound awful. Start with the manufacturers recommendation and adjust from there.