First and foremost I'd like to say that it really doesn't matter what others think, as long as you are happy with your arms. That said I definitely think this version is better; the red charges on the chevron really bring the arms to life, as does the galley in base. I still have some reservations about the lion's head on the chevron. On my monitor the shield measures 2.25 inches from top to base point; if you reduce it to 3/4 of an inch (the size it might be on letter paper, a calling card, or the rim of a plate) I'm not sure the lion's head erased would be all that legible (it might be mistaken for a bit of current stuck to the plate).

Since a galley on a gold field figures prominently in M'Donald heraldry, might I suggest you consider doing away with the embattled chevron and blazon your arms simply: per chevron azure and or in chief two swans argent, in base a galley. By eliminating the chevron you would at once gain more space for the swans and galley-- which seem to be the focus of the heraldic statement you are trying to make-- while making the full achievement readable if reduced in size.

As far as cadency is concerned, with this proposed blazon, there are three options: (1) using a black line to separate the bordure from the base; (2) using a chequey bordure; (3) and the instance I would favour, placing a small crescent between the swans. Thus, you would inherit your father's plain coat, and your younger siblings could then difference by bordure in the usual fashion.

Back to you!