The Halder Simplex mallet and the Lixie (both 14 oz) arrived one day apart. Initial thoughts:
1) The Halder Simplex has a nice slimmer handle, great for prolonged use when lots of pounding are done. Its soft face (blue) is too bouncy, meaning greater force is needed for assembly work. The hard face (white) is definitely too hard for any softwood. I'll reserve it for hard maple, etc.
2) The Lixie, costing almost twice as much as the German mallet (because of shipping/custom fees), has a fatter handle with a cheaper finish look. The larger handle is appropriate for heavy pounding though as you get a better grip.
Unfortunately, the soft face (brown) came with two hairline cracks and seems to have been used (and returned by someone?). I didn't try it, fearing that it could break apart. It has been reported to the seller for a response. But the soft face feels pretty hard, not like the Halder Simplex's blue face. Its green and black faces are both tough. The green one did not leave much a dent on softwood unlike the black one or the white face of the Halder Simplex.
In conclusion:
The German mallet is a good buy, suitable for light to medium pounding given the handle (could the handle stand heavy pounding? I can't tell given the limited pounding I tried). I wish they offered a medium face, not too soft and bouncy. I'll see if I can harden the blue face....
The American mallet with its narrow body of the head is great for hitting in tight corners, and it doesn't leave a hard mark as much on the softwood with its green face. I suspect the green face and brown face will work quite the same. No bouncy feeling of whatsoever. Useful for precision/controlled hits and larger casework.
In 6 months after I use them enough, my views may change. Now, I've just added one more project to my "Winter Projects" list: A Mallet/Hammer Rack.