Preset management: in the owner's manual

Preset management: sharing presets between Axe-Fx II and Axe-Fx II XL

You can transfer presets from an Axe-Fx II Mark I/II to a XL, but not the other way around.
Yek: "When I transferred all my presets to the XL, I kept a log of changed parameter values. These are the ones you may want to check before and after transfer:
- COMP — TYPE and SUSTAIN and MIX and AUTO
- PEQ — FREQ TYPE (bands 1 and 5), GAIN (all bands), LEVEL
- GEQ — 16k slider, LEVEL
- TREMOLO — LFO PHASE and START PHASE and WIDTH
- MIXER — BALANCE
- CHORUS — LFO PHASE"

Beside the factory presets, you can load other users' presets into your Axe-Fx. Presets have a .syx file extension. Presets are available through the user forum and Axe-Change for example.
If you use Fractal-Bot, Axe-Fx II: Axe-Edit or a MIDI librarian such as Snoize SysEx Librarian (Mac) or MIDI-OX (Windows): make a connection between your computer and the Axe-Fx, load the .syx file and send it to the Axe-Fx. The Axe-Fx is always ready to receive presets in this way. If you upload a preset onto the Axe-Fx this way, the preset is not yet stored on the Axe-Fx but kept in a buffer. If you want to keep it on the Axe-Fx, select a preset slot and save it.
Preset files are also kept in bank files. You can use Axe-Edit to pick individual presets from a bank file.

Cliff: "The II does a few things different to try to make patch changes more seamless." source
Cliff: "Dropout is only 20-30 ms. If you are experiencing more than that then your MIDI controller is not programmed properly." source
Firmware 11: "Improved preset switching speed, in some cases drastically improved".
For gapless switching, use Preset scenes.

Cliff: "There are two possible destinations for a preset: the edit buffer or a defined preset number. The destination is encoded in the data. If it's not going to the edit buffer then the preset was harvested from a hard drive somehow. When you load a preset with Axe-Edit it sets the destination bytes. However if you use a librarian then the preset may go to the edit buffer or to a defined preset location depending upon the destination bytes. You can identify the preset destination from the data. If the seventh byte is 7F then it will go into the edit buffer, otherwise it will go into preset memory. For example: F0 00 01 74 03 77 7F 00 goes to the edit buffer whereas F0 00 01 74 03 77 01 02 will go to bank B preset 2 (patch 130)." source

Besides the Store > Swap feature on the hardware, you use the software editor to move presets around.

When saving your own presets you have to overwrite factory presets on the Axe-Fx II. You can restore these at any moment from disk after downloading them from Support.