Hosting HTML, CSS, React JS We application in Netlify

I am in my beginning stages of my freelancing journey, I am build Websites and Web Application for my Clients for less price/ Zero price. I have registered domains for these websites but I am using Netlify/Heroku for hosting. Even though I am charging less money I don't want my Clients suffer by an means like slow loading or maintenance issue. So I wanted to ask experts in the forum that is it a right choice to stick on to Netlify/Heroku for hosting or should I go for premium hosting? if YES please suggest me good hosting platforms. Thanks