Just stop here if you have tickets to Rigoletto. If you plan to see it later in life I am sure you'll forget this blog post by then.
I went to Wikipedia the afternoon before I went to see Rigoletto and my eyes went to the words "when his daughter is murdered." Damn! Self-spoiled. I shut down Wikipedia immediately.
Then, during the opera, the daughter, Gilda, opened her mouth to sing, and I was horrified, because the singing was so gorgeous, and then she was going to be murdered any minute. So I spent the whole time poised for her murder (and there are many opportunities). I should not have worried, because she is murdered in the penultimate scene, and then we discover she isn't quite dead yet and she almost sings the very last line.
If she hadn't sung so well I would have wanted her dead long before then, because she is infuriatingly stupid. Falls in love with the Duke while he's impersonating a student. "I love him!" She continues being in love with him ("But ah luv him" she warbles incessantly) for the rest of the opera, even though he is proven to be a man whore who thinks women are fickle. (Fickle, as he sings in the aria everyone knows:
... which ends up being a satisfying plot point.)
As for plot: our Duke was hefty and our Gilda was wee, and there is no way Rigoletto could confuse one for the other, even if they were in a sack.
So, it's hard to say if I preferred Rigoletto to Marriage of Figaro. I preferred the singing in Rigoletto, but I didn't want to shake everyone in Marriage of Figaro.