iCloud email works perfect. I've never had any issues with iCloud email at all. Plus it works brilliantly with iCloud itself (Obviously!)
I never had any issues with Mobileme either. I was surprised to hear that people were having issues. I've had way more issues with the iCloud email and calendaring functions. WAY more.
As far as spam: Out of all the email accounts that I have had, the iCloud account was the worst hit by spam, and took the longest to stop. And along the way I found out that 'rules' in iCloud and the mail app are so much more tenuous than 'guidelines' that they are almost useless. I setup several rules to automatically send spam to the
spam@icloud.com address, and it almost never worked properly. And I say 'almost' because I can't confirm that it ever didn't work, but it looks like it never happened.
I've got Hotmail, and somewhere a gmail address, and a Yahoo address as well, but I only use the iCloud and Hotmail addresses. And yes, I am probably one of a half dozen that actually pays for Hotmail.
I was treated like a pariah at a tech conference when I admitted to paying for Hotmail. It works for me, and it's cheap.
But anyway...
Is iCloud email worth it?
It works like a champ for my nearly 80 year-old mother. Don't knock 'easy'. I hated her Yahoo email account as it seemed to be always on the fritz, and she was always calling me panicked that she 'broke Apple' or 'crashed Yahoo' or broke her computer...