If you're processing more than a couple thousand a month, their rates aren't great. You're giving up around 0.6 to 0.8 percent of all of your revenue by not using something else. The interface, features, etc, are great, so it might be a decent tradeoff at lower monthly rev amounts. At $50k/month, you're giving up $400/month.
Haven't heard this one before. What does it do besides accepting payments? Can you also buy things with this service?