I've used the RE50. It's a dynamic, very resistant to wind (as it is) and is nearly indestructible.
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Ty is right in that, in order to spec the right gear, more information is needed. So, I will give my usual answer when confronted with such a question:
Now, in reply to Ty's post, I'll add some of my experience as a person who works in live sound...
If there's a PA involved, there will likely be less trouble (read: feedback) if a directional microphone is used. Whether it's dynamic or condenser won't matter all too much. As long as the off-axis pickup pattern of the microphone is uniform, any feedback can be dealt with a minimal amount of equalization - though, more likely, the feedback is due to less-than-optimal microphone and/or speaker placement, be they monitors/floor wedges or main speakers. EQ will never fix problems that are due to that.
Condenser mics tend to have a smoother response over their frequency range (though many are tailored and have boosts/cuts here and there) and their pickup patterns tend to be more uniform, both on- and off-axis.
Dynamic microphones are )more often) cheaper, more-durable, and don't require phantom power, which every condenser mic requires. The reason that the "venerable" SM58 is chosen so often is not because it sounds amazing (though I've heard worse), it is that the microphone's sound (timbre, for you musicians) is consistent through the product line and engineers and artists know what to expect. It lessens the unpredictability of the situation, which is fairly unpredictable anyway.