First, Rar and Ace compression rates are not so much better than zip. About 1-5% only.
BUT1: Memory issue:
For example Rar needs swap file about 3mb!!!! and moreover it takes lots of RAM in addition.
BUT2: Speed issue, no comment, you can see difference even in PC. Zip work at least 2 times faster.
So these compressors (may be) are good for PC, but not for Handheld device.
Good point. What about zlib? I believe it is sort of like Zip with regards to RAM requirements/speed but has variable compression rates from 1-10 (of course 1 is least compression/faster speed and 10 is best compression/slower speed). I think standard Zip comes somewhere between 6-7.
I think that both of these apps have these compression rates already. There are settings for optimum performance, like fast or slow or multi tasking or speed.
I think that these guys have exhausted all the possibilities even before we have thought of it. They are the ones who created the apps, and besides, it's already in the later versions, and not the neo beta versions.
Good work for Stacker and Space Doubler. It really helped the 7650 developers and users to put more apps into our babies.