I have both systems for X1C and only dry box for MK4
Both are pretty good , but i find that AMS keeps the filament drier for long periods , the dry box once it is off after a few days may be a week with silica in the middle. may need drying again , while the AMS keeps it dry for months easy . But the AMS does not dry the filament only keeps it at certain level, or may be just tiny bit. Also for X1C AMS you need the extra silica compartments as the stock one is not enough plenty 3d models around and i replace the stock one as well with the 3d printed and loose silica
Edited: read in details this thread gives You all information
I’m fairly new to 3d printing, but I print a LOT of PETG. I have come to the conclusion that any filament can be wet. I don’t believe that a dry box, by itself, is enough to dry wet filament, it can only keep it dry. I don’t think that blast drying will dry the entire roll. How could it dry the filament deep in the spool? Seems unlikely to me. I have had many rolls where the printing degrades as I get deeper into the spool, even though I print the entire spool in less than 48 hours AND its printing from the AMS with fresh desiccant. If the filament is on a cardboard spool, the cardboard is another source of moisture (another reason to never put a cardboard spool in your AMS).The most reliable system I have found is to print directly from the heated dryer with the dryer on( have a cheap SUNLU drier) . As filament unspools, the inner filament is exposed, heated, and dried. This has always produced the fewest problems for me. I hate doing this, and I would much rather just plop it in the AMS, but my experience is that strange things can happen to your PETG print as you get down toward the end of the roll otherwise, and I’m tired of filling my trash can with failed PETG prints.