I've heard that the Sennheiser EW100 ENG kits are excellent value for money.

http://www.sennheiser.co.uk/uk/icm.nsf/root/21418

A new set from LTF costs about 670 quid. I know that some of the owner/operator teams use them and my regular soundie has a kit which he bought as a back-up, all of which sounds promissing,

I have no experience of them myself, since at work we tend to use the old (mega-f..ing-expensive) Sennheiser 5000 system which is luverly but is way out of my private bracket.
If you manage to use the EW100 in the field, let me know what it's like!