Arbor vs Narus comparison?

[andy lam]

Recently I've been searching for something that is comparable to Arbor to see 
what else is out there.  Someone suggested Narus.
 
Anyone out there have an opinion regarding the 2 applications and their 
differences?  Or another application that is worth noting?
 
I am currently using Arbor Peakflow for Netflow analysis against my 
peering/transit traffic and their Security suite to identify DoS, etc at the 
edge.
 
Feel free to contact off-list.
 
Thanks