Aegis was great when it came out, but as time's moved forward, they've released many more sets, and never really went back to make the others competitive again. Isn't Aegis essentially a Mk X set?
It's not BAD, and easy enough to get, but just not sure it's worth the outlay. Borg, MACO, and Omega are all better if you can run the STFs (Borg set can be had easily, just 15 EDC now, and you can get 4 at a whack by running the wednesday STF bonus). The Dominion set (from the FE) is probably the best of the easy/free ones right now at Mk XI. Breen isn't worth it, but easy enough to collect, probably a decent set to grind on as you level up, although you'd have to KEEP doing it, as it's another one that sets itself at the level you are when you pick it up.