Series 1 and 2 were good, series 3 was the same which made me wonder whether they were taking the series forward at all. Adrian Lester left series 4, which, sadly, made that series the worst of the lot. His character makes the show, more than anything else.
The new characters are introduced well to the series. Albert starts the series in prison, still doing his thing whilst inside. Ash and Mickey start the series off as a pair, employing the help of Eddie who had to close his bar and become a waiter. Emma (Kelly Adams) is a great character and actress, she plays her part really well. Sean is where the bad reviews start to set in for this series, some people don't think the actor playing him is up to it, some people think the writing for the character is not up to it. My opinion is that he brings change to the show. Danny Blue was a funny character but a bit of change is what is needed. His character is well written and in the beginning it makes you wonder whether he will mess up the con due to his inexpertise, but later on he makes his mark, especially in the following series.
Some people will miss Marc Warren playing Danny Blue, but I believe that his replacement brings new life to the show which was much needed. Jaime Murray will not be missed, I think her replacement brings a lot more personality and sexiness to the show.