cap coly ships

They colonize faster, and their colonizing abilities have bonuses as well. TEC's give you free fully built extractors when you colonize (1 at rank 2, 2 at rank 3). Advent's reduce costs of all planet upgrades by 20/40/60% for the ranks. The Vasari one gives a structure build rate increase (I forget the exact numbers). The Vasari colonizer is comparatively the least "useful" for its bonus, but the ship itself is fantastic all around, so even as a combat ship it's a great first choice.

Vasari colonizer cap (Jarrasul Evacuator) gives a 20% structure build rate increase. same bonus at each of the 3 levels for the skill, it just lasts longer at higher levels. 

i actually think its a better bonus than the TEC bonus. resource extractors cost almost nothing (250 default, only 150 for most TEC players because of their civic research tree) so the comparitive value of free extractors is pretty low, possibly as low as 300 credits. the only benefit from them is getting to harvesting resources that much faster, but its only a difference of about 60 seconds since extractors build pretty fast. you also don't get any bonus at all at level 1.

i think the Akkan is by far the weakest colony cap ship. weak gunnery, fragile compared to other cap ships, and not particularly useful special abilities (Ion Bolt is pretty good, the aura is sucky, and its got a weaker colonizing ability than the other 2 in my opinion). 

Jarrasul Evacuator and Progenitor Mothership are both great though. Good bonuses on the colonizing ability (the advent bonuses are particularly great) and VERY good special abilities. Jarrasul's Nano Dissasembler is an absolutely lethal direct damage ability. Mothership's Shield Restore is a core ability in advent fleets when combined with Iconus Guardians. 

With the exception of TEC, the colony caps are also the most powerful all-around caps for each faction.  This means that you don't only get a free super-colony ship right off the bat, but also you're set for the long-term with a well balanced capital ship. 

The big issue with colony frigates is anti-matter.  Until you have the anti-matter regeneration upgrades, they take several minutes to go from 0 to 90 and actually be able to colonize a planet.  After one use (or several jumps), their anti-matter is typically empty, so in most cases you need to build multiple colony ships to keep your colonization going.  The colony capital ships, however, regenerate that anti-matter faster and there's none of that waiting involved.

While I originally thought it useless, Targetting uplink is usefull for making flak more accurate vs DC and increasing the range from what I understand.

Yeah all akkans needs is to have the free extractor at lvl 1 to be just as awesome as the rest.

this is a good point. the accuracy bonus is also very helpful while fighting in asteroid fields (-20% hit penalty) and against a Rapture Battlecruiser with Vertigo (gives -10/20/30% hit penalty depending on level).there's also a pretty noticeable enhancement for move+fire damage since ships seem to suffer both range and hit penalties while firing on the move. on the other hand the Akkan itself is very slow so its easy to outrun the aura in a chase situation. its not useless, i just think its not useful enough compared to other buff auras. the Halcyon's rate of fire increase or the Rapture's squadron damage increase auras both puth Targetting Uplink to shame in terms of overall effectiveness.