Clarification: I'm recording at live band shows in a small space. The band is performing for an audience, and I'm recording off of the sound board. When I use my condensers, I tend to get a lot of feedback. I'm usually micing every instrument / vocalist.
Are you recording each channel individually or sending a mix? Is it a dry signal from the direct-out of each channel or are you sending post-eq/post fader? Is there any other processing applied? Compressors, gates, reverbs or delays?
Your problem is caused by bleed from every voc and instr mic picking up the sound from monitors, PA, guitar amps and whatnot and repeating the signal over and over, effectively mudding up the sound. Over a live PA this isn't a huge issue, but a recording done this way will be shite flushed down a toilet and no godforsaken wondermic will get around this problem.
If you're doing a multitrack of dry signals (the best way), you can do some cleaning work in post. Get into the stems and isolate the music parts and remove everything else around them and you should aim at having at least the lead vocalist using an in-ear-monitor. The SM58 works best because of the pick-up pattern being very sensitive at close range and practically null at anything over 1 foot. By all means experiment with other mics, but my money is on the 58. I have spent the last 10 years as a live engineer (recording countless setups) and I'm yet to find a mic that works better in those conditions.