It depends on what you want and how driven you are to get noticed.
- Do you want more comments/subs/views?
- Do you want a loyal fanbase that's interactive but not necessarily big?
- Do you want a little bit of both but is not sure where to post to get that?
There are pros and cons to both websites, and it can be a bit of work in building your audience. There are also a few other topics just like this with a few more insightful answers.
Overall, a lot of people do favor for posting on both to try and get an audience. That way, you are able to see which site works for you. It also helps to make sure other people know about you and your work.
It helps to advertise your work in forums or on your social media, where you already know a lot of your watchers have been following you. It also helps to be interactive with other readers and creators outside of your work so that you can build relationships and connections.
That's one of the big parts of getting out there: helping others help you and vice versa. 