Strength
PETG is about five times stronger than acrylic and is considered virtually unbreakable in normal conditions. Acrylic can crack or shatter under impact and can have sharp edges.
Color
Acrylic has excellent optical clarity and is available in optically clear to opaque white. PETG has a blue/green hue.
Scratch resistance
Acrylic is more scratch resistant than PETG because PETG has a softer exterior.
Cost
PETG is slightly more expensive than acrylic.
Temperature
Acrylic softens at higher temperatures but doesn't melt until it reaches 320 °F (160 °C).
Other uses
PETG is a thermoplastic polyester that is easy to thermoform and is a good choice for machine guarding, especially for medical devices. Acrylic can be used as a lightweight alternative to glass in applications where optical properties are important.