We tested the local multiplayer here in the office and it worked pretty smoothly. One big issue I had was that you can always see the names of your opponents (through walls and across the map), so there is no sneaking up on people.
The editor is definitely useful for creating skins, and there are a few presets if you don't want to do it yourself. You can edit every surface of your blocky character, but you'll only be able to use your skin in the desktop version of Minecraft.
The store lets you buy the very important Elixir of Resurrection, but makes you pay $1.99 for each one. There are other glamor items like the crystal sword or the miner's pick, but they're hardly worth the price. The same is true for the extra ammo or health.