Need feeedback on M 90mm lenses

[meastman@adobe.com (Mark Eastman)]

I'm trying to decide on which M 90mm lens is best for what
I do which is mainly ersatz photo-journalism and a fair amount
of street shooting. I find I will often make use fo f2 in low
light situations (i.e. in a theatre, gallery reception, etc).
I'm considering a 90mm lens. I like the 90mm f2 Summicron with it's
built-in shade and it's faster aperture. However, it's a real HONKER 
in terms of it's size & weight compared to the 90mm f2.8 Tele-Elmarit.
Does anyone have any insights on the major differences in the
performance of these lenses wide open or in general that are worth
mentioning?

Thanks ahead of time,

Mark Eastman
meastman@adobe.com