I did enjoy the last book and the whole series (don't if there'll be more - if there'll be more I'll be reading it). I enjoyed reading about Tony and Mac and the kids. About their struggles to be a family and about every day life.
I do think that the author could have done without the crimes in each book. I wasn't really invested in any of them - not even the first one. I think the love story itself would have worked well enough without the crimes. With a few small changes everything would have led to the same outcome.
So I wouldn't recommend reading the books if you do it for the cases. Do it for the boys and the love story and the family and the 'Awww' and you'll be very well satisfied, I'd say.