I would throw a third option into the mix... Kitty litter. I built my first tupperdor with heartfelt beads and it has worked great, virtually maintenance free and still spot on after almost a year. However after reading the threads here I have used Kitty Litter for two more tupperdor a and a coolidor since then and have had the same great results at a fraction of the price. Bovedas are great but the will dry out and while they can be "recharged" it's a little more tedious and time consuming than maintenance on KL or beads. Just my $.02
In fact in hindsight, I think the most important thing I learned was patience. Take the time to calibrate your hygro right, and give it time to acclimate. Don't stress if it drops a couple of points when you open it or if the temp drops in the room. They are all great humidifier options, just adjust slowly and let it settle.
