Can't comment on size because I don't have one. You can judge the Dish photos as well as I can.
As for speed, the WJ uses the same faster processor as the "Joey 2.0." Unfortunately, I know of no way to know if you will get a Joey 2.0 or Joey 1.0.
For that matter I don't know if there have had any confirmed reports of a Joey 2.0 in the wild, or any hands on comparisons of 1.0 vs 2.0 (but I don't follow the forum as I once did).
A Wireless Joey may be the only way to be sure to get the faster chip.