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Micro strip lines are more susceptible to moisture that is always present in the air accumulating on the micro strip line circuit and this will detune the micro strip line circuit.
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Frankly, I disagree. Susceptibility to condensation is primarily a function of an objects surface temperature versus the dew point of the surrounding air. Water will condense just as readily on the windings and core of a traditional balun/matching transformer given the same environmental conditions. The dielectric properties of a transformer will also be affected negatively when subjected to moisture. In fact, I would expect a damp wire wound transformer would hold moisture longer as there is less air flow between the wire and core where moisture would cling than on a flat exposed surface. Ultimately the design of the DB4E balun provides plenty of shelter from rain, ventilation and drainage of condensation. The millions of functional strip-lines and wire wound transformers currently in service (some decades old) provides a strong argument that both are capable of reliable operation despite moisture in the air.
To give credit to the traditional balun/matching transformer, it generally offers greater bandwidth than a strip line or coax balun. So a wire wound transformer would usually be the better choice for interfacing an all channel antenna to the down-lead.
Enough nit picking... I hope ADTech's response has answered the OP's original questions. Unless @Psdstu invites further discussion it seems best to consider this thread closed.