At a quick read, Aramco doesn't seem nearly as interesting as Petronas does.
Aramco is an oil/natural gas company, and that's about it. It's really really big, but that's just because it owns a lot of other oil/natural gas companies.
Petronas is an oil/natural gas company too, but they're branching out into other forms of energy as well. Sure, they probably make all their money on oil, but at least they're trying.
I assume that when oil/natural gas becomes a bad business model, that Aramco will simply purchase another energy company, or that the ownership (Saudi Royals) will just let it whither.
I guess good for Mercedes to take their money, but it's not very exciting to me.
(I DO find it interesting that Aramco started as a tendril of Standard Oil. I know 'late stage capitalism' is thrown around these days, but Standard Oil really is the poster child of 'late stage capitalism')