The quote is certainly irony but not, I think, simple irony or, more accurately, simple sarcasm. Your reading is too trite given the context; and far too tame for ironic Austen. The full quote is:
Originally Posted by JBI
I understand Mr. Bennet to say:
Elizabeth had the satisfaction of seeing her father taking pains to get acquainted with him [Darcy]; and Mr. Bennet soon assured her that he was rising every hour in his esteem.
"I admire all my three sons-in-law highly," said he. "Wickham, perhaps, is my favourite; but I think I shall like your husband quite as well as Jane's."
Yes, Wickham is untrustworthy, scurrilous and unscrupulous. He has ensnared my daughter and others before her, but now that Wickham and Lydia are respectably married, life must go on. No matter how despicable he has proved, he is nevertheless a companionable and ever charming son-in-law. Despite or perhaps because of duplicity, Wickham is the more admirable in that he is better company than the stiff and proper Mr Darcy or the sociable, malleable Mr Bingley.
Always complex, hiding away from society as he does, Mr Bennet is beyond crude and simple sarcasm.