Love both shows and only would only just rank DS9 ahead of TNG... mainly because of the inconsistent first 2 seasons of TNG. Both shows just have far too many classic episodes and moments to dismiss and I thoroughly enjoy watching both sets of characters.
Though I must admit, TNG has a more nostalgic feel to me since I grew up on it and ToS while DS9 was harder to see when it first aired for me. I didn't get to fully enjoy it until the DVD release. Kinda sad that it doesn't have the same childhood Sunday marathon feel that I always get when watching ToS and TNG.