If you like the Nikon, then you made a good choice
The truth is that most cameras these days are soooo good that the gear isn't the issue. Nikon generally has very good AF and low light capabilities. If it does what you want, then shoot with it and be happy. I specifically was going for small form factor and was just shocked at the image quality.
The biggest issue these days is when you have invested in a system. For instance if you have a bunch of nice Canon lenses, then if you decide to switch to Nikon or Sony it's going to end up costing you a lot more than just the cost of the new camera. In my case I had three Canon lenses (and another two at work) but I was enamored enough with the Sony to sell everything off. Luckily I had glass that is fairly popular so it was an easy sale. I've already bought 3 of the E-mount lenses for the Sony, have one on order, and likely will end up with the other two primes at some point. I'm holding off buying any more A-mount glass for the a77 as that is for work and if I need other glass for work then I'll figure it out later. For now the g/f is happy with her 18-250 though I'm not
