Doug is going to do a Savor the Flavor article on these sometime soon.) I like blue common having one common hard counter (meaning a spell that can counter anything such as Cancel) and one soft counter (meaning a spell that can only counter a subset of things or allows the opponent a way to work around it, such as Mana Leak)
Added as wildcards, they've been mechanically designed for use in the Commander format, and won't be available in the set's precon Commander decks - so if you want these, you'll have to start tearing your way through a few booster packs
Pick your favorites, put them in your deck and battle!
Champion deck sales have opened a new way to both enhance collections and let players get right into the game, and we'll continue to make the process clearer, better respect your collections (particularly different printings), and try new things in this space
The land stays an Island until the flood counter is removed, even if Xolatoyac, the Smiling Flood leaves the battlefield