In my experience, Verizon is the best if you rarely travel outside the U.S./Canada, whereas AT&T is the better choice if you're a frequent international traveler since their international plans are more reasonable and their network tends to be more compatible with other networks. As far as what model to get, it depends. What do you use your phone for mostly? Do you prefer a large screen to see better or a smaller, lighter phone that fits more easily in your pocket? Do you download a lot of apps? Do you use iTunes or some other music service? Do you take lots of pictures? I have a Nokia Lumia 1020 Windows Phone, which is great for me because I'm not a huge app user but I like photography (the 1020 has a best-available 41 megapixel camera) and I use a lot of things in the Microsoft ecosystem (Exchange for work email, Hotmail for personal email, Xbox Live Gold account, Xbox Music Pass, etc.). But the choice for you might be totally different. I'd suggest you test out a bunch of phones, keeping in mind what you typically use your phone for. If you're looking at high-end smartphones, you're most likely going to go with an Apple iPhone, Samsung Galaxy, or Nokia Lumia. All 3 have their benefits and detriments, and you just have to pick which one is best for you based on your preferences :-)