You know, a nice part of this thread, was reading it while the video game fight was still playing in the background...
Anyhow, the next game session came and so I made a ruling.
Since the teleport comes from a move action, and because the spell's result, in and of itself, is no action (and is precise when the target square is viewed), then I said that you could sneak attack when you arrived.
I reason the move as any other invisible/hidden move. If the rogue could move 40' for some other reason, and was invisible, he would still get a sneak attack at the end of that move. If the rogue fired a bow from hidden/invisible within 30', he can see vital areas and sneak attack, so why not pop in with the boots and strike as well?
While there are some arguments that say Teleport makes you uneasy/unstable/disoriented, I don't see it that way, especially when your "arrival spot" is within sight. I hate to say it, but it reminds me of Dragonball Z. Pop out, pop in, strike... they never see it coming...
Again, the boots are a move action, 40' Teleport, 3/day.
Now, I might have a problem if the rogue wanted to teleport through a 10' wall (pick a direction and distance) and then happen to "appear" next to an enemy and then want to Sneak Attack. For me, it would depend if the characters were in or out of combat rounds.
If the rogue was aware of the enemy somehow and initiative was already rolled, I would allow it (for instance, creatures retreat through door, shut it, and then rogue teleports based on distance and direction only, happens to appear next to one with a standard action left.
If not in rounds, then you would have to roll for initiative/surprise once the rogue arrived to determine if he could not get the partial round sneak attack then.
Thanks for the dialog!
Aluvial