It is interesting that some draw a different conclusion on this. When I did my sound sample comparison of Ken Middleton's playing on the SK-35 and SK-38, there seemed to be a lot of difference in sound, but Ken was playing different songs. I also know Ken commented the sound was quite different.
When I did my own comparison and posted it on YT, I didn't detect as much difference, although there is clearly some, and since the SK-38 only has 12 frets, it invites harder strumming, and the notes seem more distinct on finger picking. In Thom's strumming tests, I don't detect as much difference either.
The SK-38 looks cooler right out of the box, if you like that classic Martin look. It will probably take 10-20 years for my SK-35G to acquire that dark brown patina.