An aqueous NaBH4 solution is easier to handle than powder, but it has an important drawback: NaBH4 decomposes in water. The reaction is slow, but over time, some of your fuel will just disappear as a puff of invisible gas, unless you make provisions for capturing the hydrogen gas (complicated, expensive, heavy). According to the Merck Index, aqueous NaBH4 solutions "can be kept for several days." The decomposition reaction is temperature sensitive, so don't park your car in the sun.
Regarding the two forms of hydrogen: it sounds like they are talking about different electronic structures. One of the forms of hydrogen they are talking about must be an excited state. This excited state hydrogen will react much more quickly than normal hydrogen due to energy or symmetry considerations. However, excited state hydrogen probably has a halflife of only a fraction of a second before it reverts to the ground state, i.e. until it becomes normal hydrogen. For practical purposes of hydrogen generation, transport, and storage, excited state hydrogen gains you nothing. If anything, it represents an energy loss, since the energy difference between the excited state and the ground state will be lost as heat.
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