From my experience when playing as Toss, Marauders are handlable in the early stages with forcefields and a zealot-heavy composition. In the late game when there are several colossi on the field and your zeals have charge, they are not that tough as well.

The problematic stage is the early stages of the midgame, where they have stim and are in a mass where it is hard for your slow zeals to get enough surface area on them. This is the part I have difficulties with, so I rely on immortals to bolster up my army against them. Only thing is when the opponent has good micro, he focus-fires them as you mentioned. And I don't seem to have any way to micro the immortals against this.

VR & phoenix...well,more towards phoenix i think..

at least if VR,my queenie can shoot them back no problem.
but if phoenix,1 lift..150minerals bye-bye...then,can focus kill ovies..

many toss i fought now would go fast stargate,play phoenix/VR rush...& personally i think zerg anti-air units r damn expensive in early game...plus queens take very long time to produce.around 50sec as opposed to
50 mineral marines <30sec (2 can pop out if use reactor core) & 100mineral 50gas stalkers 20-40sec (depends on chrono boost usage,warpgate tech & number of warpgates)

u can argue that queens r beefy units,but they r too dependent on creep for speed.can only transfuse when have 50 energy.plus,when being lift-off by phoenix rush,that beefy hp won't do anything good..

queens need energy buff! make them got 50 energy right after being produced...

I fear Collossus the most when I do MMM

I damn scared of whiners