It starts up much faster than the MX-5200 & comes out of sleeping much faster, but thermal regulation isn't as fast.  Soldering a ground plane is still painful.  The LED goes out, indicating its thermocouple is at the required temp, but the tip is still cold.  It's an incremental improvement from the FX-888, but nowhere close to the Metcal.

Conical tips on the T-12 are incrementally better but still suffering from FX-888 problems.  The point tends to stay cold, while the heat comes from the side.  Temperature has to be increased to get a hot tip.  Never did measure the Metcal's temperature, so it might have relied on a hotter temperature.  It might have always been 340C.  Lions use 280C as much as possible, to avoid lifting a pad & burning flux.

The rattling of the motion detecting switch is bearable & it's sensitive enough to keep it on with normal motion.  The tip being longer than any other iron ended up not being noticeable.  They might have done that to get a cold side for the thermocouple.

We've traveled far, in the last 30 years.  The 30W Archers & Wellers are long gone, though the very 1st stand from the lion kingdom's 1st Archer kit is shown.  Lions spent a lot of time grinding down the Weller tips as they eroded.  Time to discard the 15W.  Lions never got burned after switching to the regulated ones, because they had real stands.