If you are looking for an affordable Darth Vader mask for costuming then this is an excellent choice.

As others have pointed out, the plastic lenses are not of good optical quality. More on that in a minute.

I had one of the original Don Post masks and in some respects this new mask is actually better. For example, the original mask had a fairly rough interior and I had to wear a skull cap to keep it from scratching up my head. This one is quite smooth inside and more comfortable to wear. The silver parts on this mask are brighter. As far as the lenses go, they are both about the same. The biggest difference between the two masks is the price. The Don Post mask costs about $70 when I bought it in the 80's. Compare that to less than $25 for this one.

Now for the lenses. The lenses on this mask were quite easy to pop out. I took one over to the local flea market and found an inexpensive pair of sunglasses with a curve that matched closely enough, were a little larger in all directions and a good color. About an hour's effort with a Dremel and a cutting wheel, a little 5-minute epoxy and now I can see out of this mask just fine.

While that may be more effort than some want to put into this, if you are putting together a costume to actually wear for an event it's not much to do to have a much more wearable mask.