Neither Observable nor Highlight offers a free trial.
Observable is designed for Individuals, Medium Business and Small Business.
Highlight is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Observable Starts at $9/User/Month whereas for Highlight Starts at $1,000 when Billed Monthly.
Some top alternatives to Observable includes CodePen, Visualr, ibi Analytics Platform, Instadeq, Dashana, Ideata Analytics, Vizician, Zoomdata and Vizydrop.
Some top alternatives to Highlight includes IntelliJ IDEA, Codeanywhere, ShiftEdit, Visual Studio IDE, Koding, Repl.it, CodeTogether, CodeSync and Pseudocode Editor.