I like the fact that it's ad-free, stable, and that if the servers do go down, or if there are problems, we are told what is happening, and kept up to date.
There are so many so called 'free' webhosts out there that either have constant downtimes, or solicit free customers to upgrade to paid hosting, or start removing features for free hosting. I could go on and on, but i'm not going to.
x10 has none of that. Yes, it does have occasional downtimes, but we are kept informed of what is happening, and also told when it is fixed.
I have used plenty of free webhosts in the past, but my site has never had such good uptime and stability before I moved to x10.