What speakers are you using to monitor your output. Unless you have a faulty Mic, changing to a cheaper alternative will not bring Nirvana.
Nearly all LD mics are engineered with a presence boost but this is nearly always above the sibilance frequency's and just adds a sense of openness to the recording. The fact that you do not get it with your other Mic could be due to it having a suckout at just the right frequency.
Listen to singers especially close up and you will be surprised how much sibliance occurs naturally.