Favorite Netflow Analyzer/Collector

I'm looking for a collector and analyzer that will support v9 and specifically both v4 and v6 flows.

I've looked at the usual suspects: Scrutinizer, PRTG, nfdump (open source), Manage Engine's netflow analyzer.

So far I like Manage Engine's solution the best, but I'm sure I haven't even scratched the surface of what's out there. Has anyone here gone through this evaluation process and found one they like best?

I've used flowviewer in the past and liked it, simple: http://sourceforge.net/projects/flowviewer/

plixer is also okay: http://www.plixer.com/Flowalyzer/flowalyzer.html

Thanks, I'll take a look at FlowViewer