[Callers] Earset microphone recommendations

I am in the process of buying a Shure PGX1/PGX4 transmitter/receiver system with the intention of using it with an earset microphone, the small, nearly invisible 'rice grain' style. A friend of mine is singer and I borrowed her Countryman E6 earset (the omni-directional model) to use at a dance the other night. I really liked it though I did deal with some feedback getting too close to one of the speakers, so I'm thinking about the directional model. The E6 is however $310 http://www.ccisolutions.com/StoreFront/product/COU-E6IO5TSL-SL.prod?Origin=C ategory and so I'm interested to know what else people like and find durable. So, I'm looking for experience and recommendations on any of the following: Countryman E6/E6i (omni) Countryman E6/E6i (directional) OSP HS-09 (omni) These next three all the same rig sold under different companies MM-PSM Pro Series Earset Electovoice RE97Tx Point-Source Audio CO-7 In particular, I'm interested in knowing about the OSP HS-09 and the directional E6. Has anyone using the directional E6 had problem with the mike staying in proper position or being too sensitive? The directional aspect should make feedback a non-issue but I've been told that positioning can be a problem.... Thanks, Will -- Will Loving Amherst, MA 01002