I would say a top 7 or 8 QB in the NFL is great. If you dont think he is top 8 in the league at this point then you are an idiot.
That's highly debatable - and probably wrong since most people seem to disagree.
Flacco has the ability to play at an unbelievable level and the ability to absolutely stink up the joint like few other NFL QBs.
The top four QBs are pretty well settled as being Rodgers, Manning, Brady, Brees in some order (Brees 4th). Most people list Eli and Big Ben not long afterwards on the strength of their postseasons (which is not a great way to rank QBs but probably the best argument for Flacco and their results are better than his).
Matt Ryan is probably emerging as a consensus #7 and the 8th could be debated between Newton, Cutler, Rivers, Luck, RG3, Romo, RW, Flacco, Schaub, Kaepernick, and Dalton