Handlesbar

• provides pretty much all the features you might need for writing templates
  • layouts
    • block placeholders (contentFor hooks)
    • partials
    • built in helpers (if, each ...)
    • inheritance
  • common helpers like for loops and if statements
• easy way to register new helpers. this consolidation also makes it easier to test

Weaknesses

• An extra DSL layer over your templates
• You might end up writing a lot of helpers depending on the complexity of your templates
• passing values to nested templates become difficult to reason about

https://github.com/barc/express-hbs

EJS

• Use plain JS in your templates
• simple to learn but very powerful because you can easily leverage all the features of JS
• Extremely flexible
• easy to pass data around
• easy to extend

Weaknesses

• Barebones. You have to reinvent layouts, block placeholders, partials, inheritance...
• All the JS in your templates can get messy really quick