This is a question that gets asked regularly and to be honest its a difficult question to answer as generally comes down to personal preference but what we can do is give you the pro's and cons of both.
An electric warmer will generally not be as intense bursts of fragrance as tealight burner however you will tend to find the melts have longer lasting time period as the tealight burner. Where as a tealight burner tends to give a stronger fragrance immediately however this tends to burn off the fragrance and give the melt a shorter life.
The most important thing when choosing a burner is choose the right product for you.
If you have young children or pets then you may believe that the electric option is a safer option over the tealight burner and that would be your decision to make.