Does epoxy's final bond strength depend on its rated cure time?
I've been told by the proprietor of the local hobby shop that long-cure epoxy adhesives will be stronger than short-cure. I was told at the time that it has to do with the lower heat generated by the long-cure, but my research today suggests nothing of the sort.

The few links I pursued indicated that long-cure epoxies remain in a semi-liquid state for a longer period (duh) which allows the cross-linked molecule strings to increase in length, when compared to short-cure epoxies.

I have noted that when using 5 minute cure time epoxy adhesive, it will sometimes fail under lower stress conditions than expected, while in a similar mechanical configuration, the 30 minute stuff holds up.

In all of these epoxy references, including those for fiberglass and carbon fiber applications, it is noted that full strength will require 24 hours or longer.

One of the forum posts I discovered (radio control model building) provided an anecdote in which the OP discovered the 15 minute epoxy adhesive would shrink and crack and become brittle under conditions that did not cause similar problems for the 30 minute formulation.

I was unable to locate any solid technical papers covering research. It appears anecdotal and also my personal experience.