For the last 2 months, I've been buying this set when on-sale. Since it's release in Dec 2011, it seems to have always been under the radar due to more popular sets (Batman, Avengers, etc...). Physical in-store stock has always been hit or miss in my area. Since Oct, it hasn't really been available at least around me ( except for 1 over-priced TRU). Online inventory is still good if you want some. Note : it is already retired in all countries except the US and Canada.
I think 6862 will do very well once retired based on recently retired / soon to be retired sets like Capt America's Cycle, Wolverine, and Catwoman. Additionally, Superman has prob better appeal outside of the US ( based on recent movie research).
It is the only set that contains Lex and Wonder Woman (for now). Also the only way to buy Supes in his classic attire. The Mech-like is surprisingly good. It holds together well and looks cool with Luthor.
The set sells consistently on bricklink for $18+. The minifigs already sell decently. Superman sells $8-$11, Wonder Woman for $5-7, and Lex a paltry $2-$4 (too bad he's not wearing the green armor suit like in that poly or game box).
With the upcoming 2015 Superman II (with Bats & Wonder Woman) movie, this set should keep the fans happy until new sets are introduced with minifig refreshes.
My (for what it's worth) April 2015 target price is $60 ($75 with luck) for a set that can still be had for under $15. I selected April 2015 assuming the next movie is released in May or July because I'll be unloading my sets prior to it's release due to the probability of refreshed sets being available and pre-movie hype ( in case it tanks).