Personally I have done quite well in NFL and there are others that have also.
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> NFL data has to be the most analyzed data in the world. Where's the edge? <HR></BLOCKQUOTE>
Agreed data and games are overanalyzed. However, that can present opportunities in itself, when faulty methods of analysis are used. Bettors tend to extrapolate data when they shouldn't, and also factor in variables that cannot be used with any accuracy. If you can identify faulty analysis methods that were used in making the line, again you have an edge.
A HUGE advantage of NFL is the amount of "square action". Most Joe Citizen-type bettors will bet only NFL. Thus, there's a public bias in the lines and opportunity for value. This is of course over represented in the playoffs, but can be found to a lesser extent every week.
To touch back on over analysis - most "public" bettors are getting there information from newspaper boxscores, ESPN, SI, and "TV-games". There are a lot of things happening on Sunday that are glossed over or omitted by these sources and thus not factored in.