Do you mean decent professional hosts or decent ro hosts (if any ...)?
From what I heard, big servers told me free DDOS doesn't protect them at all. They are also "all talk" and when you need better protection they'll ask for $ or you move.
Yup.
They don't really ask for more money, just tell you that you are out of luck. The best part is when you aren't even being ddosed. It's one of the 15 other servers on the same machine.
If you are a new server, don't get high on your horse. Tread ddos waters carefully and don't piss off the wrong people. We have ddos protection, but if someone claims they can ddos my server, I make sure to be polite to them just in case they really can. We don't give into their demands if they ask for them though.
My point is this:
If someone says something along the lines of "hey I can ddos your server if I feel like it."
Bad response: "Well fck you!! I'ma ban your face all the way to your grandma. "
Possible good response: "Must be nice having all that power, hope you don't use it on us

" - add the frikin smiley it makes everything better
If they make demand then you are left with several choices. But if you give into their demand you might as well shut down your server.
Just my own experience and advice, take it how you will.