Okay, so I've only played the demo of this so far, but I think that's enough for me to make strong assumptions about the game. I mean, look at any Sonic fan site, they made up their mind about the game long before they ever touched it. Why can't I do the same? Anyways...
Sonic Boom is about a blue hedgehog called Sonic and his friends Tails (a fox, natch), Knuckles (who is a creature I've never heard of), Amy Rose (also a hedgehog) and Sticks (who may or may not be related to Marine the rat-coon) running around at the speed of sound-- sorry, wrong game, uh... doing stuff. There's apparently a story where they find this dude or chick or whatever called Lyric (it's a snake either way) who's doing what Eggman does on the show, minus the whole being the comedic foil thing. I can't explain the story too much because I've only played the demo (much like actual reviewers, I didn't get a free copy of the game), but it seems pretty sound to me. Besides, if you're playing a Sonic game for the story... go play Super Mario Galazy or something.
The gameplay is not as Sonic-like as you'd probably expect, but it's from a spin-off series with the only relation to the main Sonic series being... well, Sonic and crew. Even then, they've gotten a dose of TP for good measure. Anyways, the gameplay is not bad in my opinion, though it is slightly awkward to get used to at first. The graphics look great, though they don't look as good as, say, Watch_Dogs_Licking_Their_Balls, but then again it's a Sonic game and it's aimed towards kids who know that the world has more colors than brown, light brown and dark brown. The sound is pretty damn ace too.
If you want a unique Sonic experience, get Sonic Boom for 3DS or Wii U. It's better than what other reviewers say (and they're only saying that because Sega dared not to give them review copies). And don't listen to the online Sonic fanbase. They hate anything that's not 20+ years old. I say BUY IT.