Well, according to:
http://elite-dangerous.wikia.com/wiki/Ships
Anaconda HP (Armour): 945 + Military Armour 250% = 2362.5
Corvette (Armour): 666 + Military Armour 250% = 1665
Cutter (Armour): 720 + Military Armour 250% = 1800
Anaconda gets the most out of Military Bulkheads (+250% Armour = HP) compared to the other two ships, so in theory can take more punishment. However, Corvette has slightly harder armour, and Cutter has better shields. All in all, though, they are, on paper at least, all fairly balanced - what the Anaconda lacks from the Corvette and Cutter, it makes up for in pure hull hit points, and has plenty of internals to make is just as deadly as either the Corvette or Cutter - though with the introduction of the new military slots, the Anaconda slightly loses its edge with just 1 compared the 2 the Corvette and Cutter enjoy, as it'll mean less module or shield protection.
In a nutshell:
Anaconda has 8 weapons of all varying types, 3x Large being the majority + 1x huge. Enjoys largest hit point pool. Good speed. Good maneuverability (for its size).
Cutter has 7 weapons - no small (better than Anaconda), but lacks 1x Large (Anaconda better) - most shield HP. Excellent speed - bad maneuverability.
Corvette has 7 weapons - only 1x large, has 2x huge, 2x small, 2x medium - least hull HP - arguably best maneuverability. Okay speed.