I'm going to agree with Lady Damia here. Your best best is to make a character on each of the shards that you are thinking of transfering to.
Transfering your characters and items is a time consuming and expensive thing to do, so you'll want to be sure you make the right choice.
By making a character on each of the shards in questions, you can get a feel for the shard's community, guilds, general population totals, housing availability, friendliness of the people, and even who is willing to step up and help a player new to the shard.
Give it about one week of actual playing on a shard, then try another.
My take of the shards:
Legends: See Damia's reply. Hit it right on. Great shard if you're looking for a tight knit community, friendly people, and lots of open housing.
Origin: Actually has less players than Legends. Traveling the land real quick, I actually found a couple spots to place a keep. Still has good people, but off peak hours are very slow. Great shard if you're looking for a quiet peaceful shard, friendly people, and tons of open house space.
Atlantic: The most populated shard in the game. With lots of people on at all times. Lots of guilds to choose from, great for doing champ spawns and dungeon crawls. Events here can get a little crazy and there's not a lot of housing room. You can still find small plots around, but even 18x18 plots are extemely hard to place. Great shard if you're looking for lots and lots of people, lots of active guilds to choose from, champ spawns, active PvP, factions, and the thrill of finding areas to place your house.