The iphone 6 was a huge hit when first coming out, and is still a good phone. To answer concerning what tower, if you purchase the straight talk one, it will only connect to a verizon tower. That's it. It will update to the latest ios, 10.3.3. I used wifi to do this. Has lots of settings and you can customize. The camera is a good one but the 6s has a better one, but you will have some nice pics and videos. The loudspeaker is plenty volume and clear, and the ringtones are nice and clear. The earpiece for calls can be less than adequate depending on the call you connect to. Overall, the volume could be a little better. But some of us just need to have our ears cleaned. The size is perfect. Not huge, not small, but right in the middle. By the way, the best small one is the iphone 5se for only $159.00. Connectivity is good with 4g lte and you can browse with pretty good speed. Hope this helps you decide.