I've read a few works with guns in it. One specific example was the Legendarian Chronicles, whose author's name is eluding me right now. Now wait, it was Chibi Pika's work. Yeah that's right! The fic centralizes around Team Rocket, and they happen to use a lot of guns. I mean it's fine as long as it's not too overpowering, like the way this fic was written. The grunts use guns, which makes more sense than them using stupid Raticates and Zubats, and the higher-ups battle Pokemon more. They still use weapons, but it made sense. So no, I don't hate it.
Real world locations? Well, Unova is basically New York. How do you think that would work? The Empire State Building isn't exactly there, nor the Statue of Liberty, and blah blah blah. But it doesn't really bother me. The setting, to me, isn't a big deal. As long as the writer can portray a scene correctly, without causing a wreck, it's fine. The writing's more important. I'm more worried about prose than a setting. A few fics have Pokemon in the real world, like a dude was from Texas and had a Tauros. So not a big deal.