Having had both the 38 was just a little too small to navigate and to read.
IMO the 42 looks fine.
One thing you may find with the 42 is you'll be right in between the S/M band being too small and the M/L being too big.
Go with the 42
I use both. I have a 38mm for running and a 42mm for the office. I like the 38mm because it's lighter when I'm out on a run. I also think the 38 looks better on my 165mm wrist. I only bought the 42mm because I thought the touch targets would be easier to hit. They aren't. If feels about the same to me. But the battery is longer.
To my eye, the 38mm looks a tad small but the 42mm is a tad big (don't shoot me, just my opinion). So I don't think either is an obvious choice over the other. In that case, I would personally go with the 42mm.