I heard good things about the Mobil 1 20-50 weight V-Twin oil. I did a change in both 6.2s today alone with replacing the standard MerCruiser 3" tall oil filter with a 5+" tall Fram HM5.
This filter appears to have a drainback valve where the Mercruiser filter does not.

Of course it started raining so I'll have to wait to see if there is a difference in oil pressure or drop in oil temperature over the Mercruiser 25w-40 oil and filter.

Anyone else running the V-Twin oil?

I have never been a fan of Mobile one. I have a friend with 750 supercat engines and swore by mobil and was always tearing up lifters which in turn tore up engines. Now for 3 years he is using joe gibbs mr50 and has had no failures. take it for what its worth.