Yeah, they put the spark in him. At the very end of season six Spike got his soul back and the fans thought, "why do we get a second Angel?"

Why did he get his soul back anyway?
After he almost raped Buffy Spike fled into a desert in Africa to meet a demon. He wanted to be again who he was a long time ago. Spike meant to be the vampire who he was before he got the chip into his head. But the demon knew what Spike really wanted. And after some tests he gave Spike his soul back.

Has Spike changed?
He had changed for a few weeks maybe. He was confused, scared, in pain. He didn't understand what was going on in his head, neither did anyone else. But after some time he was able to handle it. And now he seems to be the old Spike again. He hasn't really changed. And after all he did it only for Buffy.

Is he a second Angel now?
He's a vampire and he's in love with Buffy. In my opinion that's the only similarity the two have.