I loved threes, Played it for close to 20-30 hours during winter break. As soon as 2048 came out, I managed to get to 2048 on my second try based on my experience with threes. I play 2048 in my browser whenever I have a spare 5 minutes, and when I'm on the Bus, I still frequently hop into a quick game of Threes.
The mechanics of the two games are very similar, and obviously 2048 is a direct descendent of threes - but I wouldn't go so far to say that one is better than the other.
Threes has claim to originality, and first publication, so significant credit does need to go to Asher Vollmer, Greg Wohlwend and composer Jimmy Hinson of Sirvo for their original invention.
But, Threes does have some "issue" - one is really poor startup times. It's slow enough that I am more likely to play 2048 in my browser, than bother firing up Threes on my iPhone. The piece assignment in threes, is also somewhat less pleasing to my experience than in 2048, for whatever reason.
Also - sometimes you are looking for nice quick fun - I get a nice rush of (finger mashing) 2048 to the 512 stage, and then very, very quickly racing to 2048 instinctively (plus the crush of defeat if I make a flickering mistake and get my pieces out of place).
Threes requires a lot more attention - I can't really play it at full-key-flick-speed - Not every game has to be chess.
If you read through the emails, and design history on the "making of" - it really, really emphasizes how damn hard it is to build that original kernel of genius. And then the piling on of all the clones/knockoffs/descendants shows how trivial it is for others to stand on the shoulders of genius.
One challenge of the AppStore (and obviously the Android stores, and simply by definition the Web) - is that there is no real way to "reward" the original developers for their many months of hard work, when others can simply clone, tweak the artwork and mechanics (or in the case of Zynga, just the artwork) - and release and market their own duplicate of a game after someone else has done all the hard work.
But, sometimes this opportunity to reinvent is good - I've tried a lot of podcast apps - because I listen to podcasts for about 4-6 hours/day, and, while "Cast" is my current preferred App, I'm looking forward to what Marco does with Overcast. I would have hated it if we couldn't have lots of diversity in that marketplace. (And I would have shot myself if I had to use Apple's (original, horrible) "reel-reel" podcast player).
Another approach though are apps like Vesper - It's "another" notepad app - but the developers (Q Branch's John Gruber, Brent Simmons, and Dave Wiskus), took months and months to polish and refine till it creates a totally different notepad experience (and, in my opinion, the best one on the iPhone) - isn't it good that they had the opportunity to build something in the notepad category, in a different way?
All in all though, I hope that Sirvo's Asher Vollmer, Greg Wohlwend and Jimmy Hinson get the credit they deserve for building the "first of".