Oscar, I have just completed an upgrade of our all of our wireless systems. It was not an easy task.
For years I have shot with nothing but Lectrosonic. I had a chance to demo a few wireless systems Azden, Sennheiser, and Sony. I was not impressed with Azden and Sony. Sennheiser on the other hand is well on it's way to making a great wireless system. I felt it fell short on function over form and would not be up to the riggors of dialy ENG use.
I decided to pick out of habit, reliability, range, and cleanness in frequency to go with the Lectro UCR201. It is a synthesized wideband UHF system which features 256 selectable frequencies. Tracking front-end in the receivers. Dual-band compandor. Advanced diversity reception. In short you could hang someone over the edge of the Williams Towers and still pick them up clear as a bell on the street.
You really can't go wrong with these microphones. If you have nay more questions drop me an email.
Peace,
Matt