There are several versions of the f/2.8. The newer manual focus versions are better than the older ones. The autofocus ones are slightly inferior, but the D is very good nonetheless.
The f/3.5s are good - the AI especially - but, of course, 2/3 stop slower.
Personally I'd take a good, clean f/2.8 over an f/3.5, assuming the same pricing, but if the f/3.5 is sufficiently cheaper it would certainly do the job.