I don't really know. All the different formats has me confused most of the time as to what my ears could discern the difference between. I was reading somewhere that the AAC was a better choice given file size and performance. I'm setting up a 32 GB USB stick for my new Chevy Colorado truck that has the Chevy MyLink system in it. Sounds great to me. Needed to get as much as I can without sacrificing too much on quality onto the 32 GB. After all it is a vehicle so the listening environment isn't always the best. Here's the formats that the MyLink can support.
From Chevy......
We recommend using 32 GB,
also the formats will be as follow: FAT32, NTFS, HFS+ for the file format.
Supported File System Structure
Up to 11 folder levels
Maximum Number of Files Supported
10,000 (combined songs, pictures and playlist)
Supported Audio File Formats
MP3
MPEG 1 – Layer 3
MPEG 2 – Layer 1,2,3
CBR (Constant Bit Rate)
VBR (Variable Bit Rate)
Mono and Stereo
WMA (Windows Media Audio)
WMA 9.0
Bitrates between 5 Kbps and 384 Kbps
CBR (Constant Bit Rate)
VBR (Variable Bit Rate)
Sampling Frequency between 8 kHz and 48 kHz
WAV
Sampling Frequency between 8 kHz and 48 kHz
AAC (Advanced Audio Coding)
MPEG 4 Part 3
AAC+ V1 and V2
Sampling Frequency between 8 kHz and 96 kHz
Mono; Bitrates between 8 Kbps and 576 Kbps
Stereo; Bitrates between 16 Kbps and 1152 Kbps
LC Profile
OGG Vorbis (.ogg)
Sampling Frequency between 8 kHz and 48 kHz
AIFF (Audio Interchange File Format)
Sampling Frequency between 8 kHz and 48 kHz
3GPP (.3gp)
Sampling Frequency between 8 kHz and 48 kHz
Playlist Formats
M3U
PLS
WPL
ASX
B4S
XSPF