For more information there is a technical paper in the SANS reading room at: http://www.sans.org/reading_room/whitepapers/forensics/reverse-engineering-microsoft-exfat-file-system_33274
and there is a blog at http://rshullic.wordpress.com
There has been a lot of inaccurate information posted on exFAT, even Microsoft can't publish the proper detals, as they (Microsoft) published bad information in the KB for the Windows XP/Server 2003 patch to add exFAT support to those systems.
So, first, let's talk about file size: Microsoft incorrectly published the maximum file size as 64ZiB, and as a result the Wikipedia and other websites followed along. The truth is. the maxium file size, as in NTFS, is 16EiB because the file size, i.e. the number of bytes in a file, is stored in a 64 bit number. However, since the file system can never be larger than 128PiB, which is smaller than 16EiB, you will never reach the theoretical maximum anyway. However, this is larger than then the 4GB limit of FAT32.
Suitability: exFAT was designed for removale media. NTFS is not suitable for removalable media, especially since NTFS uses a lazy write, which means that data and control blocks are bufferend into memory, and an abrupt disengage of the media could result in data loss. Today, USB media does come to mind, but between the SD card association and Sony with the Memory stick, they have adopted exFAT as the exclusive file system of SDXC and XC memory stick media, which is used in cameras, cell phones, GPS, etc and between SD and Sony, that is 90% of the markey. However, each camera manufacturer has to pay Microsoft like $300K each for the license to the specifications. But almost anything can be formatted in exFAT (excpet floppies) and USB is not the only removalable media out there.
Compatibility: exFAT is right now restricted to the Desktop/Server platforms of Windows XP (SP2 & SP3 with a patch), Vista (SP1 and above), and WIndows 7 (RTM). There is not Linux, MAC, or other OS support right now. All consumer devices, except Windows CE and the camera companies that licensed the specification, can NOT support exFAT. (There is actually a TV manufacturer that also licensed exFAT). This means that PS2, PS3, XBOX, probably most Blu-Ray Players, cell phones, etc don't have exFAT support. even devices that have SDXC imbedded card readers can't support exFAT unless the OS installed on those devices can read/write exFAT.
Speed: NTFS is not necessarily faster than exFAT since NTFS has a lot of overhead. [I have not benchmarked this]. NTFS is faster than FAT12/FAT16/FAT32 because NTFS has the free space allocation map, but exFAT now has the bitmp as well. Also, in exFAT - the FAT itself is no longer used unless there is file fragmentation, i.e. the file can't be written as one set of contigious blocks. This also reduced a lot of overhead because the FAT was a set of controls blocks that required a lot of I/O. One of the problems with FAT16 and FAT32, when used in cameras was finding available free blocks. The fle system overhead slowed down write operations. When you look at the future SD4.0 card specification, it calls for a bus speed for i/o transfer of up to 300MBps (that is 2.4 gigabits/second). We are currently at SD3.0 with a maximum bus speed of 104MBps, and the SDXC memory cards are currently being toted as class 10 but claim a 30MBps speed and cost $400 and above. Since these cards are all new, it is going to take a few years to get a reasonable prive point. But a 48GB SDXC card is the equivalent memory space of a dual layer Blu-Ray disc, and can be re-written.
NTFS/exFAT: exFAT calls for file permissions and fault tollerance (which I believe the Windows CE version has), but is not in the current exFAT 1.00 specification. So, it is possible that exFAT wil get a lot more NTFS features. But today, exFAT has one (1) FAT where FAT16/FAT32 have 2, so exFAT actually has less fault tollerance on the desktop today than its predecessors.
Micorosft never supported creation of a FAT32 file system larger than 32GB, but it will support a FAT32 system formatted for larger than 32GB, although some utilities won't work correctly, such as some setup utilities.