Anything's better than what you get with the provider.
First, what speeds are you subscribed for?
Second, find a cable modem that supports higher than that speed and is on the the compatibility list for your provider.
It should be plug and play replacing their cable modem, but you also might need to call them if it's not.
Seriously, get a modem rated for faster speed than you get and your speed will go up. I've always had good service with ARRIS modems, the Motorola ones will work to spec but the ARRIS ones are more reliable and are faster.
I would suggest finding out what modems/routers your ISP supports. Certain ISP's wont help you with any issues you may have in the future if something were to go wrong with the modem/router you decide to go with. My ISP told me that if one of their customers has a Nighthawk router, they will not help them with any issues because in their contract, they stated that they've had issues with that router and cannot do anything to fix the issues with that router.