While comparing OCR Engines in UiPath, any of the current platforms have the potential to perform well. The key differentiation between each one of these tools depends on its intended use. For example, if we want to process raster or vector PDFs only, Abbyy would likely be the best option. It is full of features for PDF processing, however lacks the functionality of handwritten text recognition.
Microsoft OCR excels on handwritten processing, however the integration seems too complex and not easy to use with 3rd party applications. Google on the other hand is quite applicable for both handwritten and PDF processing with the engine accuracy being the only potential stipulation.