Using XFS means, that you have to deal with fragmentation of your files. Disregarding fragmentation, XFS is a wonderful filesystem which never caused any problems here.
To check fragmentation, we use the xfs-debug tool in read-only mode:
xfs_db -c frag -r /dev/sdX#
At my server it would look like that:
stargazer ~ # xfs_db -c frag -r /dev/sda7
actual 376951, ideal 373687, fragmentation factor 0.87%