The string-based content evaluation targets string builders, when the final content is assembled by concatenating strings during program execution with inclusion of evaluatable expressions. The final content is submitted to the method oServer.oHTML.EvaluateContent(), which returns all resulting content with all expressions enclosed between delimiters <% and %> evaluated.
The text-block-based evaluation targets multi-line text with evaluatable expressions. The text block is included between delimiters <#text:variable name#> and <#endtext#>. The specified variable within the begin text block delimiter gets the resulting content of the text block with all expressions enclosed between delimiters << and >> evaluated.
The advantage of text block evaluation is its visual presentation - the entire multi-line code is easier to analyze.
The advantage of string-based evaluation is performance, especially when strings are built in tight loops, and then evaluated.