I find both shows emotionally gripping, but you need to catch the right episodes, and you need to have been watching from the beginning. There are still moments in Farscape that still give me chills, and I've re-watched the show at least a dozen times (and I'm doing it again right now!). B5 is also fantastic; the first time I watched it, I did what the OP is doing. I bought the first season on a whim and blew through it in a week. I have re-watched B5 about 4 or 5 times, and I still think it's excellent. They're just very different animals, and I find myself fortunate that I am able to love them both.
Farscape, however, is my favorite show of all time.