Did some little comparison table (.ods / LibreOffice) for units. Not finished yet (a few units are missing, and in the Civ Column is incomplete).
Some data points I found interesting:
Naked Fanatics have, despite the big complain thread about them, not overly impressive combat stats
The P2 Champion Infantry Swordsmen of Athenians and Carthaginians have insane stats cost-for-cost, and have the additional bonus to be fast
Maidan Guard have really bad stats if you compare them to other fast infantry; they can only keep up thanks to the 20% damage bonus from Steel Working
Elephant Archers are cost-for-cost about twice as tanky as other archers and still deal about the same damage
0AD_Unit_Calculations_028_01.ods
Beginning with the Alpha 27 series (code name Agni) we had a first Alpha 27 Agni - Patch Release 1 (a27.1.) There are signs we'll see a Release 28 Boiorix - Patch Release 1 (v0.28.1) in a few weeks.
It's not the standard type of latency lag there. Only some sluggishness during a long match with many, many units.
It's gotten much better since A27.1.