Our caller uses a headset, and it works well. It took a long while to persuade her to not put it in front of her mouth ( the response is tailored with a treble lift to allow for the lack of directional treble when worn to the side)
UHF is good. Diversity receivers are IMO essential - if you move around signal cancellation and dropout can be a problem with non-diversity systems. Switched frequencies are good - twice we had to reset the frequency once to avoid broadcastin dance music to evensong in the church next door.
If you're used to using a hand/stand mic you'll miss the variation in tone and level that you can get by being closer to or further away from the mic.