People saying Hearts of Stone is better are definitely correct, but Blood and Wine is not exactly of low quality (it still oozes CDPR's quality set in TW3s original release).
I wouldn't say one is better than the other. They both complement each other, whereas one is smaller, tighter and focused on a storyline the other is bigger, gives you a complete new area to explore with lots of sidequests and a branched storyline that comes together at the end.