Here's Mew with the Zip Cover.
Here's a close up of the front. Without the cover.
20th Anniversary Mew and Takara Tomy 2013 Mew without flash
20th Anniversary Mew and Takara Tomy 2013 Mew with flash.
The material of the 20th anniversary mew is a crushed velvet fabric which makes it shiny and smooth but rough when rubbed the opposite direction. The 2013 Mew is Velboa fabric which is softer but not as soft as Minky. Both Mews are pretty much the same size and made the same way. I think the 2013 Mew is a little chubbier but you hardly notice a difference. I plan to keep mine in the package as I think it looks nice with the cover. He makes a lovely display piece.
I would go to your local Gamestops ASAP as quantities right now are very limited. Mine only had 2 mews and 2 Pikachus. They probably will get more throughout February but get them early as they have no idea when they are getting their next shipments. The anniversary plushies cost around $16.99 at GameStop.