I used a June Taylor pressing board with a rotary cutting board on the flip side, for many years. It warped so bad, I think it's ready for the trash. The cutting board pulled away, but I kept hot gluing it back together. If you don't use it much, it's great.
I watched Sharon's video and finally made one for myself. It's really nice. But it's brand new. Time will tell. Home Depot sells a 4'x8' sheet of OSB. I cut it into 8 peices. I'm keeping 3 and will figure out what to do with the other 5. LOL The cost of the whole project was about $70. Plus the three days it took me to make them.