You will indeed see a clear difference. In this case, size does not matter.
A scan made from film has better/"cleaner"/"crisper" contrast, and is
sharper. It just looks better, even in small sizes.
I know, because i used to scan prints quite a lot before i began using a
film scanner. (And yes, both flatbed and film scanner are good, i.e not to
blame for the difference.)
;-)

My experience scanning images from my Lubitel (yeah, I know...) has
been that the images scanned from the negative using a flatbed with a
transparent media adapter are massively better than those scanned from
the print.

In particular the detail in the shadows that isn't that clear in the
print is much better in the scans from negative. The dynamic range is
wider and it's genuinely noticeable even on small images for the web
(say 600 x 600 pixels).

Here's a scan from a piece of film:

http://www.mcgrattan.f2s.com/lub_film.jpg

here's a detail from the same scan:

http://www.mcgrattan.f2s.com/lub_film_detail.jpg

Here's the scan from the print:

http://www.mcgrattan.f2s.com/lub_print.jpg

here's the same area from a scan from the print:

http://www.mcgrattan.f2s.com/lub_print_detail.jpg

The detail is taken from the darkest centre area.

The original scans were at comparable levels of detail i.e. the print
was scanned at a relatively low res and the film at higher but the
larger size of the print meant that the final images were almost
exactly the same number of pixels wide and high.

Both images had the same unsharp masking routine run on them and the
same level tweak to try and bring out comparable levels of detail in
the shadows. Neither is a straight unmodified scan - the original scan
wasn't done for this kind of comparison. But both had the same things
done to them.

Neither is scanned at the maximum resolution I had available and I
have done better scans from film using medium format negs.

Matt

P.S. The image isn't great, it's just the only one I had handy that I
had already scanned from film and from print.