Woohoo! I got my SX Core soldered in and SX OS booted up fine on the first try.
Took me awhile because I didn't want to strip any screws or knock/melt any components off the board. Also cleaning the thermal paste took longer than I thought, but some 91% IPA and a bunch of micro swabs cleaned it up pretty well. Makes me appreciate the pros on here and how quick they can turn around really good soldering jobs.
If you like electronics/soldering and want to give it a shot, go for it. (which is why I wanted to do it) But if you're unsure at all, the amount that the installers charge on here is well worth it. I think it took me about 3.5 hours and spent about $80 in tools.