which one is the most understated and elegant of these two?

I'd prefer something without monograms

it's what he likes that counts
I personally prefer leather and even more so for a man but that's just me

Problem is that coated canvas is preferable, cause it's more solid regardig stains, scratches, and water. A leather bag will get scratches and a "worn" look quite quick, and it isn't water resistant. Unfortunately there isn't any coated canvas bags without monograms and /or pattern.
 
I agree neither is "understated" IMO. The monograms see to that. LV Damier Ebene would be a nice alternative.

But if I had to choose between one of those two, then probably the Gucci as it's slightly less in-your-face than the LV.