PS. How much ethernet ports do you have in the office? Do you have 100 K ports? If not, why do you need 128K MAC's? (I know only one case, when I need so much - some kind of DSL service...
I guess you're not into metro networking.
This is one of my exceptions - you really need 128K MAC's for meto network. And, for metro network, it may be reasonable to spend time in QA'ing and configuration and select non-cisco solution - because it is a very big project. But it is exceptional case.
PPS. I do not know for sure, but 3550 should support traffic shaping, which makes bufferring. Technically, yes, CEF (with packet dropping) is not good to provide 2 Mbit by 100 Mbit link.
The 3550 doesnt support shaping of any kind, only policing (dropping packets, never buffer them). How can you advocate a switch which you seem to know so little about? I just never tried to configure 'traffic-shape' on it, so I do not know. It is great switch for it's niche. Metro LAN's is not standard switch niche, it is very special network. As I said above, non-cisco solution can paid off for this.
-- Mikael Abrahamsson email: swmike@swm.pp.se