As with most tools, it's all about personal preference. I have a wool mat and like it. However, I was curious about whether it
really did improve my pressing, so I sewed 2 identical blocks, pressed one on the wool mat and the other on a fluffy bath towel I'd folded in half. I threw them both over my shoulder onto the floor behind me so I wouldn't know which one was which (my son witnessed this and couldn't figure out what I was doing
) and I honestly couldn't tell the difference between them.
However, you've already purchased it, so isn't it a little late to be questioning yourself?