While I am not a Maui Ocean Club owner, I have stayed several times. It is my favorite MVC property. The property combined with the location cannot be beat. If I could be at any MVC resort, it would be Maui Ocean Club. I will own there some day.
For the OP, I think it is personal preference based on what you and your family needs are. You cannot go wrong with either in my opinion. Both get you Maui and beautiful resort amenities at the Ocean Club.
The older suites have a layout built by combining multiple hotel rooms vs being purpose built for timeshares from the start. They are slightly larger, have an extra bathroom, are nearer to the main super pool (good and/or bad), and may perhaps cost a little less on the resale market. They have a limited kitchen, no laundry in the room, and (in my experience) the interior appointments aren't quite as nice as the newer villas.
The newer villa layout was specifically built from the start for timeshares. Many prefer this as the interior layout flows a little better. They have an excellent full sized kitchen and in-room laundry. They are slightly smaller in square footage and do not have the extra bathroom. They are slightly higher in cost on the re-sale.
I am interested in what you choose and why, but would suggest weighing the pro/cons vs what your needs/wants are.
-Price
-Number of Bathrooms
-Full or Limited Kitchen
-Laundry In Room or Not
-Building/View location
-etc