I always basically grouped the batsmen into separate tiers.
S tier (players who were untouchable for very long periods)
Ponting, Lara, Tendulkar, Smith
A tier (all time greats)
Kallis, Kohli, Dravid, Hayden, Sangakkara, Chanderpaul, Waugh etc...
B tier (very good players who just weren't top tier)
Clarke, Amla, Langer, Martyn, de Silva, Pieterson, Strauss etc...
C tier (players who were ordinary but had the ability to occasionally do something extraordinary)
Stokes, Watson, Flintoff, Bell, North etc...
Marsh tier (players who are consistently mediocre and/ or only ever perform in low pressure situations)
Marsh, Marsh, Wade, Bancroft etc...
I place Kallis at the top of A tier.