Discharge curves for an M1 10 cell pack at around 13 amps and a 20 Cell (24V) 3Ah Sanyo NiCad pack at around 14 Amps.
I used a Medusa Research Power Anaylzer Pro to graph the cells.

The M1 pack was slightly warm at the end of the discharge, while the NiCads were getting uncomfortably hot.

So the M1 pack delivers a similar amount of energy to the NiCad pack (more power for less time) but is only half the weight - 0.9 kg vs 1.8 kg.

In Terrorhurtz, we currently run three 24V packs of NiCads in parallel, giving a nominal capacity of 9 Ah.
To maintain a similar capacity, we are planning to use four packs of the M1 cells, giving a capacity of 8.8 Ah.
You would also tend to use more packs of Lithiums to ensure that the packs do not get to over 60 ºC. Unlike NiCads, if M1 packs get over 60 ºC, it will significantly shorten their life.