I like Copper and Modern. I get why people would choose Booker, cuz he's also very cute (although he looks like he's really stoned lol). But to me the classic look like an outhouse. XD No offense to anyone who likes it, I think it looks cute in rustic towns. The modern station is just better looking IMO.
I actually forgot all about the difference in police dogs depending on your station... but I chose classic because it fit the look of my town more. I plan to replace my bridges with zen bridges whenever someone finally decides to suggest them to me, so I figured classic would fit the part.
I prefer the look of the Classic police station more than the Modern one, so I chose that one. I do prefer Copper over Booker though, but I guess you can't always have the best of both worlds.