The Plantronics we used in Oz were good but did have reliability issues; seems like they were in the fixer shop at least annually.
The Sennheiser (spelling?) we use in Ireland (I think that's what they are) seem to do the job fine, but I find them a little top heavy (mine falls off when I tilt my head) and I'm not a fan of the double ear muff only option.
If you are in the job of buying for a facility have a good look around at neighbouring units etc; if you are starting a new job, you'll find that BYO headset isn't usually allowed.