[Oblarg]

449 has used quick-frame extensively every year that I've been associated with the team. It's a very nice material.

That said, the connectors do not have the strength of proper gusset plates, so you must reinforce them in high-load situations.

Also note that given the nature of the connectors, they're less tolerant to errors in framing member length than a match-drilled gusset plate construction - it's rather hard/annoying to push the connector "not quite all the way in" in a way which allows you to keep things square if the lengths of your framing members are slightly off.