Used a Weber q on our last boat. Like that one for a boat grill also. Surprised no one else was disappointed with the grate.Since you'll be borrowing it, I say yes, it's worth it, depending on what you plan to grill on it.
Steaks, Burgers, dogs, sausages, yes.
Chicken, ribs, etc., no.
Like Dough13, I kept mine on my boat and used it almost every weekend. I'm on my 2nd WGA.
My issue was that you can't get far enough away from the burner for any type of slow or indirect cooking.
That said, I haven't used mine in probably 6 years.