I think that if you hold onto your iPhone for more than two years the 8 probably isn't a good upgrade to go for. My reasons are based on the assumption that the X style is going to be Apple's focus next year and onwards. I think that next year you won't have three different new phones, but only two, a standard size and a plus size in the style of the current X, and maybe a new version of the SE. If you buy the 8 or 8+ you will be stuck with the old style iPhone for two years or more while the next few generations of iPhone all receive iOS updates and features based on the new design and new gesture based UI. I also think that the price on the 2018 "X" style phone may come down to similar prices to the current 8 and 8+. I think the X and 8 this year are a result of Apples supply issues, not been able to get Oled panels in enough numbers, and hopefully by next year they will have solved this problem (we know they are already trying to ensure they have multiple suppliers of Oled next year instead of been reliant only on Samsung) On paper the 8 and 8+ are still great phones if you absolutely most upgrade this year and don't want to wait for the inevitable delays or the extra cost of the X, but I think 2018 will be the year Apple brings this new technology to the masses successfully, and this will be a more exciting year for a upgrade!