Not only is the AI very tough and a real challenge in AIC
What I also like about AIC is that you have the option to get the population mass up with starliners at a nice slow easy paced game.
OR
AND what I really like about AIC is that you have the
options to get the masses up with out Starliners for a more rapid pace game.
AIC has more Colony options then se4 and it only takes 1 year and 7 months (17 turns)to upgrade a city from a Settlement with about a population of only 30 and way less time at a higher population
Also with that 30 population it only takes 5 months (5turns)to build a Colonial Settlement and to upgrade that to a town about another 8months (8turns) or like I said
1.7 Years (17turns) at 30 pop and 2.4years at only 11 pop {{{this is how it is in AIC}}}.
In se4 after you build a few Mining Facilities on a 102% non-breathable planet what option do you have then for Colony development?
With AIC you can build Cities not only on that good of a planet (+100%) but even on a planet with 50% resources and still make a whooping profit.
So for example on a Planet I start by building the approprate or needed facilities and then with the Last slot build ONE Colonial Settlement and upgrade it to a City and then do another and another as you can see with AIC the Colonies do have the same options as se4 and with much, much more
I am not sure where 100 or 500turns comes from to build a simple city in AIC
But I can asure you it is much - much less then 50 turns, unless of coarse you have only 1 pop
and then again
only with ONE (1) Population in about 10 turns with no Starliners or even any Pop Transports adding pop to that Colony you can build that city in about 2.3 Years from a small Colonial Settlement of 11 pop=
THATS ONLY 23 turns 
The more Pop the more laborers the faster and more productive the project
[ January 22, 2004, 17:28: Message edited by: Grand Lord Vito ]