It was the newer square Centinela bottle. Not having tried the older bottle I could not comment on the difference, even were I able to remember! I thought it to be fine but not great and as I recall in the same price range as the Siete Leguas. Of the two I would probably choose the Siete Leguas but maybe because I am more familiar with it.
If I am just sitting and drinking tequila neat then for me at least the Excellia anejo is worth the extra premium. Not really any comparison between it and the other two. But then I value an anejo that can brink a bit of sweetness and depth but still hold onto its agave roots so to speak.
Excellia is cognac/sauternes aged. If you like that, you should try the Don Pilar Extra Anejo. It used french limousin casks to age as well. It's one of my very favorite tequilas. If the $130-140 price scares you off. The Don Pilar Anejo is stellar for $35-40 as well.