I can attest to the shear grunt of the Metcals. I've got an SP-200 and the other day I happily soldered a piece of medium duty stranded cable flush to the middle of a solid 160mm x 100mm ground plane, with a mere 1.5mm chisel tip, no fuss, no muss, no hanging around waiting for it, only took 2 or 3 seconds, no problem. This is only a 35W iron, but it delivers that 35W directly to the very tip of the handpiece; don't be fooled by the apparently modest power levels.