CPL,
The con is definitely the cost. At $8 a quart, RedLine MTL costs about twice as much as Honda MTF and about four times as much as regular old 10w30. Additionally, RedLine does not recommend extended drains in the tranny as there is no filtering mechanism. So you pay more and don't get the extended drain benefit like using synthetic motor oil. Those are the only cons I can think of.
The pros are the same as any synthetic based product. This stuff just doesn't break down as quickly as an organic oil.
Considering RedLine's reputation, I don't think you can go wrong with the product. I've certainly been happy with it.
Bogatyr