This depends on a wide variety of factors.
What country are you from? and what’s your goal?
I would say both are best for beginners. Even, you can use these both programs on your website also.
If your goal is to make seven figures or more - I would go with Clickbank.
If your goal is to make $5,000 - $10,000 P/M without promoting any “Weight loss” programs or MMO programs and just drive a huge volume of traffic - I would do amazon.
I am an affiliate of both Click Bank and Amazon. There is no question you will get a much higher payout with ClickBank. There is no comparison with the amount of sales you will make with CB compared to Amazon. Most products on CB are niche products which appeal to a very small number of buyers. and I have a friend who does and he told me that you need a higher sales volume to make six figures with amazon than to make it with Clickbank.
You need to do a very good job at selling if you’re trying to make Clickbank work for you - there’s huge competition for products prospects have unheard of! With Amazon, you’re really connecting the people that want to buy something with the product - they end up buying it through your Aff link to make you a commission which is a good thing.
I rely on higher payouts and lower volume of sales and conversions so Clickbank is a much better option for me.
If you want to rely on a higher volume of sales and conversions - Amazon would be the right thing to do.