Let me say up front that I am an unashamed Husky man, but I have run Stihls, (under sufferance).
Forget the 391 it is an absolute POS! Yes, I have run one.
Secondly it depends what you cut and how you cut it. Pine will favour chain speed, hardwoods will require torque.
The 362 may rev harder but to some degree you can compensate by lowering your depth guides and taking advantage of the superior torque of the 381. In order to preserve warranty I will assume that both saws are to be run as standard.
Perhaps consider other brands, Husqvarna and Makita/Dolmar come to mind, along with Jonsereds and try to actually run some of them in wood.
Stihl is not the be all and end all, (my local Stihl dealer has a Husky 372 as his personal saw:hmm3grin2orange
I have issues with the air filtration, anti vibe and metal quality on many Stihls, but to be fair would consider them for future purchases.
I agree with sawtroll that trial by video is a poor means of comparison, as are most advertised specs.
Pro saws would be my choice in any make and don't get carried away with bar length, it seems many see a chainsaw bar as a phallic extension.