It'll be interesting to see if you guys come to the same conclusions as I did. I remind you all not to underestimate stagger immunity, accuracy bonuses, and synergy (such as accuracy and headshot bonuses).
Destroyer:
passive bonuses: 27.5% additive, +20% headshot
devastator mode: 30% additive, max 25% RoF, stagger immunity, no dodge, magazine size bonus
other: multifrag grenades
total bonuses before headshot: 197% with 100% uptime
burst max bonuses with headshot: 222%
max effective health/shields: 825/1650 = 2475
Turian Soldier
passive bonuses: 37.5% additive, +30% headshot
marksman: max 50% RoF, +25% headshot, free reload, accuracy bonus
other: proximity mine 20% damage taken, no dodge
total bonuses with proximity mine before headshot: 248% with 42% uptime
total bonuses without proximity mine before headshot: 206% with 82% uptime
burst max bonuses with headshot: 347%
max effective health/shields: 950/1425 = 2375
Quarian Soldier
passive bonuses: 30% additive, +20% headshot
marksman: max 50% RoF, +25% headshot, free reload, accuracy bonus
other: tactical scan 25% damage taken +7.5% weapon damage taken, side hop
total bonuses with tac scan before headshot: 258% with 77% uptime
total bonuses without tac scan before headshot: 195% with 81% uptime
burst max bonuses with headshot: 348%
max effective health/shields: 875/875 = 1750
Human Soldier (damage build)
passive bonuses: 27.5% additive, +20% headshot
adrenaline rush: 70% additive, free reload
other: frag grenades, dodge
total bonuses before headshot: 198% with 74% uptime
burst max bonuses with headshot: 218%
max effective health/shields: 825/825 = 1650
Human Soldier (defensive build)
passive bonuses: 27.5% additive, +20% headshot
adrenaline rush: 50% additive, free reload, 40% DR
other: frag grenades, dodge
total bonuses before headshot: 178% with 74% uptime
burst max bonuses with headshot: 198%
max effective health/shields: 825/825 +40% DR = 2311
Geth Soldier (no flamer)
passive bonuses: 22.5% additive, +20% headshot, +10% geth weapon bonus
hunter mode: max 17.5% additive, 15% RoF, accuracy bonus, speed bonus
fortification: 40% DR
other: side hop, stupidly good melee
total bonuses before headshot with non-geth weapon: 161% with 100% uptime
total bonuses before headshot with geth weapon: 177% with 100% uptime
burst max bonuses with headshot: 202%
max effective health/shields: 412/1150 +40% DR = 2187.6
I may have miscalculated the bonuses with headshots, which is why I provide non-headshot damage bonuses for comparison.