You will have no compatibility issues. The main difference between Encode's implementation of UTF-8 and Unicode::UTF8's is that Encode uses decoding/encoding functions provided by perl where Unicode::UTF8 has it's own implementation. Unicode::UTF8 provides a consistent behavior across all supported (>= 5.8.1) versions of perl.

I wrote Unicode::UTF8 because I wanted a fast implementation with a simple api, you can read a comparison with Encode.

-- chansen