2 > 1 > 3 > 4 > 5
As someone who has heard these songs tens of thousands of times due to Battle Tower/Frontier/Subway proclivity, I've had ample occasion to judge the Trainer Battle music, though I have relistened to all of them twice already. I feel GSC wins because it's a nice fresh take on the if-you-rated-this-worse-than-third-and-are-not-in-total-love-with-the-ones-you-put-ahead-of-it-your-opinion-is-wrong RBY theme. I love how it goes from minor to major at 1:15, as somewhat of a reassurance that all in trainer battles is not necessarily serious and somber.
RBY is just "beaten" by GSC for me, fantastic aside from obvious nostalgia. ADV is "good", "lol netbattle". The past two gens are incredibly underwhelming. Even with PK Gaming's note on the Low HP theme bolstering BW's aura, it isn't really technically part of the song, and there's actually a "mistake" in the BW theme that really annoys me. It's either a mistake or an intentional "bad" variation on the "correct" Subway Battle theme (which is otherwise virtually identical), and to hear what I'm talking about, listen here:
http://www.youtube.com/watch?v=cWfP71MQusI#t=0m28s
The five notes of the bassline that are a falling scale...the fourth and fifth notes are repeated. There's seriously no reason for that, and I immediately noticed the "correct" variation when I first got to the Battle Subway and heard this:
http://www.youtube.com/watch?v=OqnpvyUPXUM#t=0m28s
I hope you can hear what I'm talking about if you didn't already notice it yourself beforehand. Again, the songs are otherwise identical so this is a total "wtf you cant even say you didnt notice that, composer". Which is not to say I'm actually faulting Junichi really, he's probably my favorite musician ever in a way lol.
Anyway, I've probably heard DPPT theme itself over 20,000 times. I earned over 7,800 BP in Pearl and over 13,000 in Plat, and 1 BP is essentially one battle (you get 7 BP virtually every time you win seven battles in the Tower), which is one song, so yeah. But it's not really that I'm tired of it or got tired of it, I could listen to songs like Dive or Bicycle (Gen III or IV) forever. It just really isn't all that good compared to Chromatics and Metallics. Maybe in a few years I'll have the proper separation from the awful, awful grind that was getting to 330 or 500 or 1,000 or 2,000 or 2,364 wins, but I kind of doubt the DP Trainer is going to overtake the ADV theme anyway.