I own both the Hot Toys and the DID Landas and I enjoy them both and have them both on display because both sport different outfits from different points in the movies.
My rankings...
HEADS: Winner;
Hot Toys
HT pros: Superior sculpt, higher quality paint, better overall size,
HT Cons: bland expression, inferior likeness
DID Pros: two heads, has a better expression, better likeness overall.
DID Cons: Heads are too small, paint is inferior, he has this sort of weird mustache shadowing on his upper lip, the heads look much better when this is removed with nail polish remover.
BODY: Winner
Hot Toys
Obviously... the DID body is bad but fits his outfit best. The HT is the standard TT but a bit shorter for Landa and I love the range of hands and the nice paint detail on the hands
OUTFIT: Winner
DID
Pros HT: Not much... nice coat. his pipe is better than the DID version too.
Cons HT: the suit is too baggy the coat is nice but leaves stains, the biggest problem is the hat is completely inaccurate. It's molded to look like the Nazi crusher cap with the fabric patches and lack of rope around the rim but it structured to look like a formal Nazi hat and has a glossy rim, like a formal nazi hat has. Basically it's an inaccurate hybrid. I redid mine to make it a fully formal hat, not quiet accurate to any scene when he wore the colonel outfit and the coat but the hat looks good. It's also too big though.
My mod...
DID Pros: Fully accurate outfit as it matches the premier formal outfit. all the badges are accurate and look great, The hat is completely accurate too, the hat is also not over sized, great tailoring but looks good only on the sub par DID body. elements of this outfit (hat, top and pants can be mixed with the boots and coat of the HT to create a fully accurate outfit as seen in the scene where he investigates the bar after the shootout).
DID cons: The cape and sword s inaccurate and useless but can be discarded. The white gloves are crappy, hard to get them to fold and tuck nicely in his belt like in the film, very finely pressed and folded.
Overall winner: HOT TOYS