I loved this series. I was a late-comer to Torchwood, but after this I bought all the box sets. As for people complaining that it was too "OTT", the first series had Abaddon, the Egyptian God of the dead!! Yes, it was "Americanised" (not a word, the term is "Localised") but that was to widen the appeal. If Russell T. Davies wanted to write a series specifically for the British fans, he never would have tried to export it overseas. Besides, it's got Bill Pullman!! What more do you people want?!?!
I did have a *few* niggles with the series: firstly, people seemed to get over Oswald Danes being an inhuman monster pretty quickly, which didn't seem that realistic a reaction to me. Yes, it was a plot point but it should have taken more than 1 episode of him grovelling. Secondly, in previous series the gay undertones was downplayed, especially in the subtle and developing relationship between Ianto and Jack, but in this one it's just right there in your face. I have no problem with that, but it was better when it was subtle.
Other than that, Miracle Day was a damn fine series, and if it is to be the last, a fantastic way to end the show.