I've tried probably 10 different ones and currently have the wireless ones from radio shack. Well actually 3 of them so I can check without opening my humis. They all seem to have varying inaccuracy. Get the beads, do the
salt test on one of the ones mentioned and you'll be fine. I would steer very clear of the brass analog ones there nice for asthetics but not accuracy. If you really want to go all out get one of
these
Totally not necessary. Cigars are fine between 62-70% RH IMHO.