One thing I like about Roberts is that he varies his introduction style from prior ring announcers, by announcing more quickly, where as Fink and Chimel seem to take their time. Although Manny Garcia seemed to be the first ring announcer to try that on Raw, if anyone remembers him.
However, I really wish Roberts had a deeper voice.
In ranking the more famous ring announcers in WWE history, here is my order of preference:
Howard Finkle is the best ring announcer in WWE history, in my opinion. Deep voice. Hit the right notes. Knew all the weights and hometowns without having to look at notes while in the ring. He is everything you would expect out of a male ring announcer.
Lilian Garcia, minus her occasional screw ups, was probably my second favorite announcer. Again, other than her screw ups, she is everything you would expect out of a female ring announcer. Beauty, excellent voice, can sing, enthusiasm that knows how to bring the crowd to its feet (if you ever saw her before Raw went on the air when she was hyping the crowd, you would know what I am talking about).
Gotta give the third nod to Tony Chimel. Pretty bad ring announcer at first, but definitely improved substantially over the years. Was terribly uncharismatic at first, but again substantially improved. What many people don't realize is that Chimel has been ring announcing in WWE since the very early 90's. Chimel has a better voice than Justin Roberts, in my opinion, and I really feel that he should be the top ring announcer in the company right now if The Fink is not going to be used.
Fourth goes to Justin Roberts. Again, quick pace for his announce style, but would prefer him to have a deeper voice. Excellent employee from what I understand, though.
And the fifth honor will go to Mike McGuirk-- Lilian Garcia's female predecessor. Crowd loved her simply because she was a woman. She ring announced opposite to Howard Finkle back in the Hogan Era, by ring announcing on Wrestling Challenge. She had a satisfactory announcing voice. She didn't screw up. Definitely knew how to engage the crowd.
With that being said, we'll have to see how Lauren Mayhew does when she starts on Smackdown.
Although, I think WWE is showing a little age discrimination to Tony Chimel with Roberts being given the spot on Raw over Chimel. Chimel, as I said, has a much better voice than Roberts. Unless the announcer is a woman, I seriously doubt the audience really has much preference over a characteristic like age as the ring announcer.
Hell, does Bruce Buffer get flack in UFC for his age? No. Chimel shouldn't either.