Any Issues Using Non-HFS+ As Data Partition?
When using a non UNIX file system, the permissions you see are default for all files, unless the filesystem logic (i.e. the driver) contains some "translation" from the actual filesystem to those permissions seen by VFS (the filesystem abstraction layer in UNIX and OS X/iOS).

Using a non HFS+ filesystem, and non UFS, will lose the permissions, but not just that - you will also not get filesystem notifications when the filesystem is close to full. Some advanced system calls (like exchangedata(2) ) will not work, either. For the most part, however, most apps don't use these features, so you should be ok. Another issue to consider is case sensitivity - HFS+ isn't (though HFSX is). Using a case sensitive fs may lead to weird results where case insensitivity is assumed, and vice versa.