@ddude: I don't recall saying that. Salamence is one of the best in the game. If you could cite this inference, it would be appreciated.
@ZLS: I was on the fourth round, right after beating Thorton the first time. The key, though, is that you trade as often as you possibly can. Later down the road, this can get you extremely superior Pokemon, like the one I mentioned, and you have a better chance of winning, especially against Thorton. When I was offered that Milotic, I had traded every time beforehand, except once, and that was a trade right before Thorton. I didn't want to ruin my setup, so that was an exception. But you just have to trade as often as possible, otherwise you can't win.
oh. You've been further than me then. I beat Thorton, then lost in the next round on my 2nd or 3rd fight. Trading is good, but sometimes I like to keep certain pokemon, but sometimes I start with awful pokemon(all 6 are bad). I've noticed that Speed can be key in many matches, since a lot of Sweepers are OHKO'd because they attack second and can't set up or do damage.
I think that Battle Factory is actually the hardest of the 5 places because of the unknown things that can happen, as well as the fact that you need to know each pokemon's purpose in order to succeed. In the Battle Arcade you can usually manipulate the game board to be good for your team, and you can only have 3 pokemon, so you don't need to know as much. Battle Tower is the same, but minus the game board. Battle Hall and Castle are unique to themselves, but Castle can be easy once you have enough points racked up. I can usually skip the final battle, making me only need to battle 6 times to win.
I think in the Battle Castle my streak is up to 28 or 35...
You can't trade from GSC to RSE can you?