I suspect that every possible comment that can be made about the inauguration of Donald Trump has been made by now, but I'll throw in my two cents regardless.
I won't miss Obama. Yes, he has on a personal level run a clean house, and yes, his family seems very nice. I try to hold world leaders to a higher standard than that. He hasn't proven effective at working with Congress, and his efforts to bypass them to pass his agenda have put yet more power in the hands of the President. I suspect he's regretting that today. And on a policy level, Obamacare was a nice vision, but the implementation has failed in largely predictable ways, because it reached too far. The American medical system is incredibly resistant to meaningful change, and he didn't take that into account. On foreign policy, he's done very little well - a lot of tough talk, and a lot of tough action, but very rarely were the two actually used on the same issue at the same time. There was no observable vision or coherent plan, and that's a good recipe for fumbling about until you leave office. The only way he looks good economically is by comparing him to the depths of the 2008 crash, and the one issue where he was uniquely positioned to make a real improvement in the US - race relations - have, if anything, gotten worse. He's not the worst ever, but I don't think history will be particularly kind to him.
The problem is, Trump has a lot of the same flaws. He doesn't seem to have the inclination to even try to work with Congress, which will be fine for the next two years but a disaster after that. His foreign policy is based on knee-jerk thinking and not any serious analysis that I can see. I think he'll prove prone to flattery(and that this is at least half of his relationship with Putin), and that's never a good trait in a leader. Now, I may well be wrong here - he is a genuinely successful businessman, and he has consistently knocked the teeth out of every single person who made a negative prediction about his chances. Even if self-promotion really is his only skill, he may well be the single most effective person at self-promotion in the whole world, and that may be good for something.
I opposed Trump in the election because I thought the dangers were too high - the danger of a large dumb war(small dumb wars being virtually unavoidable for the US), the danger of tearing apart the post-WW2 world order that has led to the longest period of peace between the major powers in world history, the danger of some completely unpredictable left-field risk doing something terrible to someone. I still think that.
But the thing about a high-variance candidate like Trump is that if he's good, he may well be very good. He's going to have a very different approach to the Presidency than anyone ever has, and while experiments usually fail, sometimes they succeed beyond anyone's expectations. I won't bet on that. I'm too much of a realist to take a gamble of that nature. Given that the dice have been thrown, though, I hope it all works out. I hope Americans are happier, healthier, richer, and more secure when he leaves office than they are today. I hope the world is a better place for electing Trump. I hope that I, and his other critics, have underestimated him yet again, and that he makes us all look like fools. I hope to someday look back on this post and wonder why I was so worried, why I was so foolish that I couldn't see how he'd be one of the greats. I don't know how he'll do it, but given how many times he's been written off in the last two years, he may well have another rabbit left in the hat. We'll see.
I wish Trump, and the United States as a whole, the best of luck over the next four years. They're going to need it.