IMO cerberus wins easily assuming engineers can delpoy their turrets. I do not think that the AI is clever ebough to target turret and nemesis instead of atlases and dragoons.
Most of the geth units would be slaughtered from a safe distance. Those slow units don't have a chance vs turret farm + nemesis snipers. Primes are the only dangerous enemies but atleses can easily pin down primes.
I think it is similar story with reapers. Most of the reaper units would be slaughtered by turret farms + nemesis before they could get close. Bansees can be pinned down by atlases. The only dangerous unit is the ravager but it is large, slow and obvious, unlike sneaky turrets and nemesis.
Collectors are the most difficult enemies for a good number of reasons: swarms, scions and floaty crabs. I don't think that swarms can harm turrets. Anyway ground units including abombs can be slaughtered by turrets + nemesis easily. Scions could do some heavy damage but once again scions are large and cerberus has tons of ranged units even draggons and phantoms can do serious damage from a distance. Flotay crabs are the biggest threat. Even though an atlas might pin them down for a while I would put my many on the crab. Butt lasors could do a great collateral damage. Yet the bubble would do nothing vs turrets. Once again I do not think that the collector AI is clever enough to target turrets and nemesis, so they will wear down flaoty crabs too.
All in all, out of all factions only IMO cerberus would function in a fight as it intended: large, agressive meat shiled units distracting the enemy forces (atlas, dragoon) while sneaky units slaughtering them from a safe distance (turrets, phantoms, nemesis).