Nadeko Sengoku

Basically Mami

Nadeko's connect and build are almost identical to Mami, except that it trades off charm for bind and increases damage instead of attack. Charm doesn't allow for increased damage from stronger elements but otherwise her connect is comparable.

MP Damage

One of the few units to damage MP, her magia will decrease 80-100 MP from the enemy depending on her rarity. This can be very useful against certain magical girl fights in events where the enemy builds up magia easily, though it has limited use in regular story mode.

Glass Cannon

Her HP and Defense stats are a bit low, much like Mami's. It'll be difficult to keep her alive in the long run unless she has good memoria equipped or her allies help to keep her alive.

Great Connect

If you can keep her alive long enough to connect, you can easily charm the entire opposing team and decimate them with your DPS. Her grass type will help her cleave through the many water element girls in Mirrors as well

Glass Cannon

Her HP and Defense stats are a bit low which will make it difficult to keep her alive in the long run unless she has good memoria equipped (i.e. multiple slots) or her allies help to keep her alive.  However, due to her highly limited status, it may be difficult to land more than one slot on her unless you've been saving up gems like crazy. With only one blast disc, she also won't be able to mete out much damage on her own.