The MFR 1300 base unit is indeed built like a tank. Apart from the faceplate (which is now black and has the Metcal logo instead of the OKi logo), it's completely made from die-cast aluminium. One weird thing: there are two holes in the bottom labeled "sleep" and "power down" - yet there are no potentiometers there or whatever to actually set anything.
Also there was no real manual included, only some kind of quick starter sheet which basically only tells you that the tip gets hot and you need to switch the device on with the on switch. Anyway, I downloaded the real manual from their homepage. Which is also pretty sketchy but at least explains that the power down time is fixed to 2h.
I understand that the "sleep function" is indeed done by saturating the core inside the cartridge through two magnets inside the stand. As only the stand for the solder hand-piece (WS1) has them, I wonder if it makes sense to add magnets to the stand of the tweezers and desolder tool as well.
The magnets inside the WS1 stand are two flat "donut segments" of about 100° each where the smaller/inner arc is one magnetic pole and the larger/outer arc is the other pole. The way they are mounted, the two magnet are pushing themselves away from each other. Honestly I'm a little puzzled if this exact geometry is needed or if it's sufficient if the cartridge is just inside a magnetic field.
Apart from the missing magnets in all stands but WS1 there are two more slightly annoying things: firstly the pump of the MFR-1300 will run shortly each time you switch it on. So if you want to use the station to solder primarily, this can be a bit annoying - especially if you decide to solder something late at night. Secondly, the cables of the tools are coated with a slightly sticky rubber. Maybe sticky is the wrong word, as it's not like they stick to your hand, but with three tool stands next to each other and the cables touching each other, there's a lot of friction and you could easily pull a tool from its stand unwillingly. This is especially true for the tweezers as they sit very loosely in their stand.
Talking of the tweezers, they also seem to take quite a bit longer to heat up. It's more like 10 seconds or so. I guess there the 60W limit kicks in. But apart from that, the tweezers are quite nice. You can adjust the fit in two dimensions (tip length and horizontal position). Also there is a mechanical switch to work either in wide or fine pitch position. Anyway, desoldering small 0603 SMD resistors/capacitors is a piece of cake with them.
The desolder tool also works pretty fine. I like that you can take of the pistol grip and use it like a (big) pencil. I just have to get used to the pump running always a bit longer than you actually pressed the button. The exchange of the collection chamber is very easy and you don't need any force like with my el cheapo ZD 915. Also you can't burn yourself because the actual collection chamber is made from cardboard. I'm just a little concerned about the replacement costs of these cardboard containers. Indeed, the containers would last for very long, but there is a small pad of fine steel wool in front of the actual (paper) filter which catches and holds the solder. You can take this out and clean it, but it shrinks each time as its threads are stuck to the solder. So sooner or later you'll have to replace the whole collection chamber just because this little steel wool pad is getting too thin. I guess I'll try to buy fine steel wool and form small replacement pads from it.