wait until you randomly generate a 5 sun map with 5 cluster with 4 randoms thrown in. Get a map with up to 300 planets... omfg.royally pisses me off that the AI runs away all the damn time. Embargo needs to have a stacked increase to warp time so my fleet can pwn them. WTF (why in this case) does it take so bloody long for 20 kodiaks to catch a single rank 2 battleship; they aren't activating their damn Afterburners!!!
With patch 1.04 I haven't had any problems with the AI running away, they'll stay and fight until they are severely out numbered.
Anyway, on topic. I just finished a 104 planet game with 6 or 7 Hard AI's and it took me about 7 hours. Games with less then a hundred planets probably take me on average 1-5 hours to complete. I have a map with 1502 planets, and if I were to even try to play that it would most definitely take me days or most likely weeks to finish it.
With most games if I play like an hour in and then save it and come back in a day or whatever I usually lose the incentive to keep playing and finish it. But with Sins I love finishing my games, its so addictive.