Anyone heard of them or used them?

I've just started researching reseller hosts, and HostFish was one of the first I saw, and what they offer looks good. I only have a few domains and sites right now, so don't need a ton of space yet. They give you 400mb at $24.95 a month. You resell that space, you can charge what you want, sell whatever amount of space you want for whatever price you want. I used the demo control panel they use, and it's easy. You can even setup control panels for subdomains.

So, can anyone tell me anything about them?

Yes, they seem alright. You could check through groups.google.com etc and see what pops up.

They have a free 24hr test drive there, so you could sign up for that and check them out before parting with your $$$$$. :)