I've always taken into the notice the hands. It was a symbol of togetherness and true to word, "We'll always be together". If the rules of the movie has been established as it is, then I would be in the verdict that he is indeed back in LA and back with his family. And yes, the totem is totally unreliable in this case. Reason being, the totem would've been locked in a safe within Mal. Hence we would know that is the first Inception ever taken in.

If things were really in Limbo, we would've been stuck with just the limbo world and not anything else. I do believe that in order for all this to happen, Cobb had to be around the world. If the rules would've been intact, he could only create it by memory. And with the Cobol Job, he had to be in reality no doubt.

So I would take this ending 2 ways. 1, he is in reality, due to the fact that he has accepted Mal being gone, and he took off his ring to signify that further. 2, Nolan is screwing with all of us because he knew spoonfeeding us an ending would probably not give us this impact to discuss this much of detail for the movie. I had a feeling he had all this planned in the first place.

Reality: No levels. It exists and we're met with colorful characters.
Level 1: Yussef's dream. Van Chase.
Level 2: Arthur's dream. Zero gravity lobby. It became zero gravity because he was freefalling.
Level 3: Eames' dream. Snowy mountains. Things did not become zero gravity (because it was way too complex for people to floating around in a snowy mountain area. ). Reason, how do you enter zero gravity when you come from zero gravity? To put simple, minus minus minus equals Plus.
Level 4: Pre-limbo. We're still in Fischer's head, and he needs to be kicked out of supposed-to-be limbo. But I don't think its really limbo because its mixed with the memories of Cobb, finally accepting his mistake and letting it go.
Limbo: Once Fischer and Adriane was kicked out, and Cobb gets back to being sane again, he's all of a sudden transported back to the beach, and it merges with Saito's dinner reception. They start to remember, and there's a gun. Totem was spinning, but still, it was unreliable to me either way.
Synchronized kick to all, except Saito and Cobb. Good for the Gun. And we're back at reality!

Remember the part where Cobb and Mal were on the train tracks? They were in Limbo. Getting ran over by it killed them and woke them up. Its a matter of how they were aware that they were in Limbo that would make them able to get out of it.

I think was the Mal was the first person who succeeded in doing Inception. The best part, it was to her own self. She locked her totem in the safe, as a signification that she wants to "keep" reality. She doesn't want to go back, and she wants to keep on dreaming. Cobb became the second when he touched her totem, which would make her lose sight of reality, and made it spin. Which would mean Mal's subconscious would implant the idea that the she is, sadly, forever in a dream.