As far as I know, there's no difference other than the packaging. The new set has the Signature Series red strip across the top and spine of each DVD and comes in a normal-style box. The old box looks different and has a slipcover that goes over it I think.

Old
New

The Lain set is down to 8 remaining, if you want it you better order fast

Ordered myself a set. Only 2 left.

Order one last week and it is still on order from manufacturer

And now its all gone, you snooze you lose.

I placed an order for the Lain box this afternoon when they had 25 left. Fortunately I didn't wait til the last minute

Shipping was $3 for media mail and $4 for priority (an easy choice). I couldn't find other bargains that I really wanted in order to get the free shipping though.

The old box looks more elegant and of higher quality than the newly released signature series box, which is simply a bundle of the 4 signature versions in a bailey box (plastic box). The old box is an actual full art box with a blue translucent slipcover over it.

I ordered the Lain set and I'm still waiting for the Devil Lady collection from Christmas time to ship.