This is an older thread by now but I learned what I came here looking for, i.e., a discussion about the available frequency bands.
A word on lavaliere mics. Someone mentioned the Countryman mics above. Yes, they are really nice and surely superior to the M2/M4 Sennheisers. But no one mentioned the Sanken mics. I had a chance to do some location sound for a short feature using Sanken mics (into the Sennheiser G3 transmitter/receive pair) and fell in love with those little gems! Well worth the cost (not cheap).
And a word on boom mics. If you have the equipment and adequate tracks to record on, use both! And I took a workshop with a gifted Hollywood type supervising sound editor/re-recording mixer who gave the tip that if you have the luxury to do so (and on my recent projects, we did!) use TWO boom mics! (in addition to your lav mics.) It really is not overkill. There is nothing better than having options when it comes to doing the dialog mix. And nothing worse than finding you didn’t get what you needed.