When dumping a large table in compressed mode, I get a memory limit error or a time limit error. ¶

Compressed dumps are built in memory and because of this are limited to php's memory limit. For gzip/bzip2 exports this can be overcome since 2.5.4 using $cfg['CompressOnFly'] (enabled by default). zip exports can not be handled this way, so if you need zip files for larger dump, you have to use another way.