People need to stop beating a dead horse and realize that the series has been turning out quality titles since Unleashed came out. I'm not saying they're perfect, but they're the best 3D Sonic titles in my opinion (going back to the Adventure games, they feel very clunky nowadays.)
I prefer Sonic, as a character, over Mario, but ultimately I prefer the Mario universe. The games also cater to different audiences even though they both originated as platformers. While Mario was a consistently quality series for a very long time, its consistency is also what has hurt it. Pretty much everything after New Super Mario Bros. has felt very "been there, done that." Mario Galaxy was a fresh idea, but all the 3D titles seem to be drawing inspiration from it now. Sonic games take more risks, and that has caused the series its own problems for a long time, but I think recently it has begun to pay off. Even for concepts that seem derivative these days, such as Sonic Lost World being called a Mario Galaxy rip-off, go beyond that initial concept to deliver something better than you'd expect.
I like Rouge the Bat. Her stages in Sonic Adventure 2 were way more fun, and better-designed than Knuckles', and it's nice to have kind of a sassy character in the modern era; considering that I read the comics growing up, the games' spectrum of female characters is much more limited. She also has the easiest stages in Sonic 2006, not that I've actually played it. She's also easily the best flying/gliding character in that game, mechanically, and anything that makes Sonic '06 easier is an instant win.
I like Sonic Lost World the best. It's the first game in a long time to really come up with some creative platforming themes, such as a fruit-juicer world. It's also part of the current generation of platformers with right-trigger sprinting and controls really freakin' well. It's light in terms of tutorial elements, which is bad, but once you get a handle on everything, it's sublime. If this was made back in the Dreamcast days, it would've crashed and burned. Stuff like wall-running would've been an infuriating mess (and it's still kinda difficult because of the poor explanation of how it works) but instead it really pushes the game to the next level.
Dr Pepper. It's an intellectual drink, for the chosen ones.