Both devices are great and very similar. iPhone 8 has a glass back and is a bit more costly to repair if broken. I'd go with it to future proof yourself longer since it just came out. iPhone 7 Plus is still a great device. We just bought our son the iPhone 7 for Christmas as it was a great price on Device Payment. iPhone 8 has a newer chip, slightly better battery, more camera improvements for Portrait mode, glass back (mentioned above), wireless battery charging and no printing on the back of the device except iPhone.