I'd go with the speedplay (well at least thats what
I did!). They are easy to clip into and out of,
they are easy on the knees and except for the titanium
models there are no weight limits.

Stor Mand you should be able to unclip quickly in an
emergency, if you can't either adjust your pedals/cleats
or change em.
I can get out of my speedplays in the time it takes to
dump over while on rollers (and i have the scars to prove it!).

Marty