I use [Zonomi's DNS hosting service] for some domains (and in fact wrote the app).
I think you're actually fine using your hosting providers DNS service (if they offer one). Since it can be easier for them to help you, for example, if your IP address changes.
I would however recommend you keep your domain registrar separate from your hosting company. Since the registrar is where you can control the name server records. Which lets you change away from your hosting company, should that become necessary. And (depending on how unethical your hosting provider is) you don't want them being your registrar and holding your domain hostage.
: http://zonomi.com"Zonomi's DNS hosting service"