As a warning, the rest of this post below the cut is quite image-heavy!
First thing's first: front view! The Mew on the left is the 2010 Pokedoll, while the one on the right is the new Mew Pokedoll.
-Both Pokedolls are pretty much the same size. However, while the 2010 Pokedoll is made of velboa, the new one is made of minky!
-Perhaps the most noticeable difference between these two Mews is the shape of their heads! The 2010 Pokedoll has a rounder face and chubbier cheeks, while the new Mew Pokedoll has a more triangular face with less pronounced cheeks and bettwer resembles the Pokedoll artwork.
-Like all the Pokedolls on Pokemoncenter.com, the new Mew Pokedoll has a detatchable hang tag. Though it's not very visible in this picture, the new Mew Pokedoll does have the longer tush tags that the newer NA Pokedolls have.
Now for the back view. Once again, the 2010 Pokedoll is on the left and the newer one is on the right. The long tush tag that I mentioned a bit earlier is much more obvious in this photo.
The 2010 Mew Pokedoll's tail is quite thin and a little sparse on the stuffing. The newer Mew Pokedoll, however, has a fully stuffed tail, which gives the tail a nice bit of volume and weight. Also, the tail tip of the new Mew Pokedoll is much bigger than that of the 2010 Pokedoll. A funny thing I noticed is that the tails, which are sewn to the back of their heads, point in opposite directions!
Side view! 2010 Pokedoll on the left, new Mew Pokedoll on the right.
The stuffing in the new Mew Pokedoll's tail really helps keep its shape when it's being laid on its side like this. The difference in their head shapes can be seen pretty well here, with the 2010 Pokedoll being more flat and the new Pokedoll being more pointed.
One interesting thing to note is that these Pokedolls seem to have different "postures". The 2010 Pokedoll looks like it's sitting up straight, while the new Mew Pokedoll looks like its leaning forward a bit. Though I didn't get a picture, I felt that the new Mew Pokedoll was a bit easier to stand up.
And finally, little miscellaneous details. Here's a couple pictures comparing the embroidery on the Mew Pokedolls' feet. 2010 on the left and the new Pokedoll on the right.
Overall, I find it hard to say which Pokedoll I like better! I prefer the face shape and tush tag of the 2010 Mew Pokedoll, but I really like the minky fabric, stuffed tail, and posture of the new Mew Pokedoll. Hope my comparison was helpful!