I vote for GON. Here's a video of the man in action, soldering some SMD resistors in place:
That's an interesting technique, but it's not quite as simple as it makes it out to be. There's already a sufficient amount of solder on the pads, which is not normal for a HASL finish. So either some solder was added prior to the video, or the board manufacturer put it through a reflow or wave soldering process to deposit solder on the pads (at which point you might as well solder components as well). Certainly it wouldn't work without adding solder first with an ENIG finish (which is generally accepted as standard for SMD parts). It's also a bit dangerous in that usage of a large thermal mass tip on small pads and components can cause damage to them that much quicker.
I'm a bit more disappointed in
this video though, as it shows soldering from the top side of through hole component, with no fillet and a flush cut on the other side. Future desoldering issues aside (can't wiggle the pin), the general guideline for TH parts is to get a fillet on both sides which more securely holds the part.
Edit: I can also vouch for Thechemist's soldering work as he uses proper techniques, standards and equipment as much as possible.