GNU tar (compiled C) is freely available for all platforms that run Perl, can't be beat for speed, and will always work regardless of how big the tar file happens to be.

(The only OS-dependent limitation, last time I checked, is that on mswin, you can't do things like "tar czf file.tar.gz source/" or "tar xzf file.tar.gz" or "tar tzvf file.tar.gz", to handle gzip compression directly -- you have to do "gzip" or "gunzip" as a separate step.)

Meanwhile, Archive::Tar tries to accommodate both uncompressed and compressed tar files by always loading the full, uncompressed tar file contents into memory, which means that it won't handle really large tar files. (In this sense, it's "less portable".)