My current impression:
The stats:
All: provide control, supply their and adjacent systems, double allied move speed
EI: 32m, 32c, 2000e
EII: 80m, 80c, 4000e
EIII: 160m, 160c, 6000e
MI: 16m, 16c, -2000e, 2 trans-shots per second, 19% attack boost, minor tachyons
MII: 32m, 32c, -4000e, 4 trans-shots per second, 50% attack boost, minor tachyons
MIII: 64m, 64c, -6000e, 8 trans-shots per second, 100% attack boost, planetwide tachyons
LI: 24m, 24c, -1000e, halves enemy speed, speed boost (of what?), advanced warp detection
LII: 48m, 48c, -2000e, halves enemy speed, speed boost (of what?), advanced warp detection
LIII: 96m, 96c, -3000e, halves enemy speed, speed boost (of what?), advanced warp detection, no teleport
Aside from high-mark logistics command stations, the current system works well.
Economic: the baseline for comparison, as its benefits are obvious (you always can use more material)
mkI: unnoticeable relative benefit compared to log Is, I never use these.
mkII: a nice boost
mkIII: for when I need all the money
Military: hold the chokepoint(s)
mkI: I never build this, because its 20% firepower increase is not worth the relative speed factor of two (and an absolute rsf of 4) I could be getting from log Is.
mkII: starting to get serious about defending a single world.
mkIII: invaluable for high-AIP games, notably fallen spire. Also convienient agianst cloaking.
Logistic: speed boosts, between econ and military in material terms
mkI: easily the best of the mkI stations; it delays enemy fleets, and lets you fight them on your terms. Combined with riots/long-range turrets, far more effective defence than mil Is, and the material gain is almost as good as the econ Is.
mkII: you are buying the improved m+c income, while preserving the speed benefit.
mkIII: same, but with a nice bonus against teleportation.
Warp Jammer: it doesn't need any changes, as it has the biggest stategic impact.
Most games, I end up using logistics mkI exclusively. If I need a stronger economy, I unlock harvesters.
In high-AIP games, I use econs internally, with milIIIs at the front. I never unlock econ or logistic stations.
I think that the high-mark stations (especially the logistics) could use a buff, preferably a k-cost decrease.