We go all the way back to stuff like Massalia, Kyrenaika, etc. we don't really have enough information to really compare. Like we know people recorded the relationship to mother cities, sometimes military alliances between them... but economically? did Sybaris export natural resources back to the 'metropole' in a client relationship? did colonies conquer their land, lease it/buy it by treaty? Did the Greeks bring slaves or enslave a bunch of locals on arrival?
and on top of that, all the poleis had separate laws & customs we can only loosely affiliate with each other. so there remains possibility for any or all the possibilities to be true for any specific colony over a specific period---but we don't really know.
my own very lukewarm opinion is that medieval italian (very complicated subject in its own right) colonies are probably what ancient efforts most resembled. and we can say those are pretty different from modern colonialism.
my even weirder addendum is that i think cultural differences between medditerrean peoples in greece-italy-anatolia (i.e. where 90% of greek 'colonization' happened) are very much exaggerated & scholarship overemphasizes a 'hellenic' influence on surrounding peoples who might've just 'originally' been much more culturally similar & amenable to living with & around greeks than greek authors' chauvinism lets on