Trying again, QoS for IP networks???

hello Nanog,

I forgot the subject, oops. Let's try this again...

A While back there was a thread on QoS, CoS for IP networks --
Interesting topic:

I'm interested what people think about this category of products. There
appear to be a bunch of vendors after this this market...

Cisco
Ipsilon
Checkpoint
Packeteer
Xedia
Structured Internetworks

Has anybody worked with any of these products? Do they work?
What about the different technologies

WFQ
CBQ
Flow Control
not to mention RSVP

Is one approach better than another.

I'd love to hear any comments or experiences

~ Marc