I'm using Sync 2.2.2 in the Yogscast Complete Pack (Edit: version 2.8.7.3 of the pack), in survival mode.
I also tested using Sync 2.2.2 in MultiMC without any other mods except the latest Forge, in creative mode.
Obviously using Minecraft 1.6.4.

I have the same issue either way:
Whenever I leave one shell and enter another, regardless of what the shell had in the way of inventory and whatnot, it is like a completely brand new shell, no experience, inventory or equipment. Galacticraft gear seems to transfer over between shells.
I havn't been able to find any information about this issue, so I figured I'd post about it here.
When shells stand in their storage units, they seem to be wearing whatever I had on them at the time I stored them, but when I switch to them they're completely blank.
Checking the CreeperHost log, the only issue that it mentions is moving wrongly, which I suppose it'll say any time you switch shells.

I have the same issue. Using DW20 FTB pack 1.0.25 which uses Sync 2.2.2 .
Logs do not show anything in particular:

2014-06-24 22:25:44 [INFO] [STDOUT] Setting up custom skins
2014-06-24 22:25:50 [INFO] [STDOUT] Setting up custom skins
2014-06-24 22:25:50 [INFO] [STDOUT] Setting up custom skins
2014-06-24 22:25:53 [WARNING] [Minecraft-Server] moved wrongly!
2014-06-24 22:25:55 [INFO] [STDOUT] Setting up custom skins
2014-06-24 22:25:55 [INFO] [STDOUT] Setting up custom skins
2014-06-24 22:25:55 [INFO] [STDOUT] Setting up custom skins

The shell is completely blank.
When putting the (seemingly empty) shell back into the storage, the shell looks like it is wearing the original armor (MPS in my case), but I have found no way to get my inventory back apart from just recovering my player data.

Oh, yeah, until I log out and then in again the shells look like they have their gear on still, but it disappears if I do so.
I suppose it's not good that others have the same problem, but a bit of a relief. I tested version 2.2.1 in creative mode on MultiMC, with no other mods involved, and that works fine.

After also encountering this issue today on the Yogscast Complete Pack (bah, wish I'd known about it sooner, lost quite a bit) I did some extended testing - on a clean installation of Minecraft 1.6.4, Forge 9.11.1.965 (same as what's in Yogscast Complete) and Sync 2.2.2 on MultiMC.

After trying multiple things, I was unable to have my inventory (or armour) stick to a shell. Inventory was deleted regardless of how far away from each other the shell storage bays were (tried directly next to each other, 1 block separate, and a few chunks separate). Number of shell storage bays also seems irrelevant.

However - armour visually seems to stick to the shell. Before switching back, it looks like the old shell has the previously worn armour. After switching back into it, armour is gone. As stated above, reconnecting also makes the armour not reappear.

Another test I tried was killing a shell, to be pushed back into the original body - no dice. Inventory did not remain.

This seems like a game-breaking flaw, limited to 2.2.2. I also tested all above in 2.2.1 and 2.2.0, and the issue did not occur on either.

My guess is that this has something to do with the way the data is restored, and is unlikely to be with saving.

Fixed in 2.2.3, hopefully.