Asymmetrical routing opinions/debate

[Drew Weaver <drew.weaver () thenap com>]

        Pardon me if I am using the wrong term, I am using the term Asymmetrical routing to describe a scenario in 
which a request packet enters a network via one path and the response packet exits the network via a different path.

For example an ICMP ping request enters a network via ISP A and the reply leaves via ISP B (due to multi-homing on both 
networks, and or some kind of manual or automatic 'tweaking' of route preferences on one end or the other).

I haven't noticed too many instances of this causing huge performance problems, but I have noticed some, has anyone 
noticed any instances in the real world where this has actually caused performance gains over symmetrical routing? Also 
in a multi-homed environment is there any way to automatically limit or control the amount of Asymmetrical routing 
which takes place? (should you?) I have read a few papers [what few I could find] and they are conflicted about whether 
or not it is a real problem for performance of applications although I cannot see how it wouldn't be. Has there been 
any real community consensus on this issue published that I may have overlooked?

Thank you,
-Drew