For tanking purposes, the dyson regenerative shield is also a really good choice. I have it on almost half of my ships, and i must say that it performs most of the times better than my maco used in 3 of my toons lol. But all depends on your build and your playstyle.
It may also depend on what you're taking. The changes to the Aegis Set with the 1 second immunity to damage is very effective to deal with a planet killer or the crystylline entity, for example, but not so helpful when you need to hold off a large number of attacks.