MIG Welds vs Brazing for simple bike hacks
The reason that brazing is traditionally used on steel bikes is so that the temper of the chromoly tubes won't be wrecked.  (The high temperatures associated with conventional welding would seriously damage the tubing.)

However, Cannondale, in their push to develop good aluminum bikes, invented the technique of rapid welding (since aluminum can't be brazed, and traditional welding worked poorly).  This technique was transferred to the manufacturer of steel bikes, which is why most modern steel bikes are welded (without lugs) rather than lugged and brazed.

The question is, can you do your MIG welding rapidly enough to not destroy the temper of the tubing?