Not terrible I guess is the best way to put it.
He normalised relations with Cuba and Iran, and saved the auto industry in the US and got their economy back up and running after the crash so I guess you could say he did a good job.
But with healthcare and so many other things like Israel/Palestine, Arab Spring, Syria/Yemen, Guantanimo and getting money out of politics an many other issues that he ran on in 2008, he has been a disappointment. And not all of that is due to obstructionist congress. His response to Snowden too.
Sneaky trade deals giving corporations mass power, mass droning, and doing groundbreaking weapons deals with the likes of Saudi Arabia and Israel.
He has tried to pander too many times to people who were not interested and people who would never ever do the same to him. (See Trump's cabinet picks.) I'll give you an example:
Comey. Democrats are raging at him which is hilarious. Because when he was installed, BY Obama they were lauding it as a smart pick to keep the republicans onside. They brushed off allegations that these security agencies were overrun by right wing types, saying it's all good and you need to keep the GOP happy by giving roles to guys like this.
That worked out well lol.
The republicans would never install left wing types to run things like EPA now would they? In fact they got climate deniers on the case.
His supreme court pick, Merrick Garland too lol. He wasn't even somebody Obama liked that much, but he put him forward to appease Republicans.
2008-16 was a missed opportunity by Obama and dipshit Democrats who did not do enough to win the other branches of government and carry out their agenda. Say what you will of the GOP, but they put the work in and energise their base. Democrats have not done that since the Bill Clinton days (if you discount Obama himself in 2008. He got plenty people energised by him personally, but none of that went to the party. Why?)
They need to work out why if they want to be in power again.