Being able to use up to your share of a VPS is why you pay for a VPS and not shared hosting. If you pay for 1/8th of a server you are entitled to use 100% of that quota 24/7/365. Using your resources doesn't "degrade" other customers' performance unless the server is set up incorrectly. As long as they can access their 1/8th everyone should be happy.
Most shared providers will charge you more if you use more CPU or require that you upgrade to a dedicated server. I'm pretty sure that any hosting company will be happy to lose you as a customer if your usage degrades the other users performance.