There are three factions Cybran,Ilumminate, and UEF. Each faction has it's own unique traits. The Cybran tend to have high attack. The Illuminate are very unique taking more of a defense strategy. Finally, the UEF are known for having good defenses and have some off tank capabilities.
The UEF are known to have very specialized units. One example is the intriguing fact that the UEF are the only faction to have separate bombers and attack planes.
The UEF also have iron hard defenses like the mass extractors and research stations abilities to be upgraded with anti-air and point defense. This is a unique ability of the UEF that many enjoy. Also combined with the energy generators that repair units is also equally enjoyed.
The UEF have shield generators that look good on paper, but they do not function as well as let on. One example is that shields underneath other shields are not protected like buildings so they all take the damage, but it is spread out. This is one flaw in the UEF. It is fantasized that this was added to even out for it's high stats thus making it equal to the Illuminate shields.
The UEF has fairly good experimentals. Their experiments tend to have high range which is an excellent advantage due to you being able to attack first while increasing defense. Many people however criticize that the UEF do not have enough damage.
Overall, the UEF have a fairly good defense and very good range. The UEF are geared more toward defense than offence. I would say that the UEF is probably best for people who like to turtle.
The Illuminate are geared more toward defence with most of their units having more health and stronger shields. They lack a dedicated navy which they make up for by having the abilty to hover, as well as the Wilfinja experimental unit.Their units are very specialized with exeption of the Wedoboth fighter/bomber.
Overall the Illuminate are very defencive and very specialized.
The Cybran are geared more toward offence. Their units have slighly less firepower, but are very rapid fire. Their units are very adaptable such as the adv which is a shiel generator, missile defence, and anti air all in one. Their units are very menuverable and fast. Their ships have the ability to walk on land with the LEGS technology.
Overall the Cybran are very manuverable and are geared towards offence.