The best iPhone ever released is always the latest one, obviously. Having said that, I think the consideration when ranking iPhones should be (1) how big of a leap forward it was technologically, (2) how much staying power it had, and (3) attractiveness of design. (3) will clearly be the most subjective. I won't rank the iPhone X since it's not officially released yet, but I'll have a go at ranking the rest:
1. iPhone 4
The design for the time was stunning, and the Retina display was the finest in the market. This phone established Apple's dominance in the high end cell phone market as it expanded beyond the original exclusive carrier, AT&T. The anticipation was unreal, with tech outlets paying thousands of dollars for prototypes before release. Holds the distinction of having the longest lifespan of any iPhone ever. Also happened to be my first iPhone. 🙂
2. iPhone 3G
Unfortunately, the original iPhone became outdated rather quickly due to how much of a speed increase 3G networks provided over the old 2G standard. The 3G fulfilled the vision of having the internet in your pocket at all times in a way the original could not with its 2G limitations. The App Store was also introduced with the 3G, paving the way for the iPhone experience we've come to know and love.
3. iPhone 5
LTE, Lightning, 4" screen. This was the last iPhone overseen by Steve Jobs, and proved to be quite the improvement over the 4S. Though it technically has the shortest lifespan of any iPhone ever due to the 5C, the design lives on in the SE. Considered by many to be the most refined design Apple has ever made.
4. iPhone 6S / 6S Plus
What the iPhone 6 should have been. Fixing all the issues which plagued the 6 (bendgate, underwhelming performance), the 6S continues to match even the iPhone 8 in real-world speed tests. While 3D Touch was not nearly as transformative for the iPhone experience as Touch ID from the 5S (though the 6S did receive an updated Touch ID 2.0 sensor), the massive performance increase of the 6S pushes it slightly ahead for me. The 6S continues to be sold, and offers the perfect gateway to the 4.7" and 5.5" display sizes introduced with the 6.
5. iPhone 5S
At first glance (and being an S revision), the 5S didn't offer much more than the 5, but looks can be deceiving. The 5S laid the groundwork for the future of iPhone and iOS. Touch ID was a massive advance in both ease of use and security at a time when many users didn't even use a passcode because of its inconvenience. The new, 64-bit iOS 7 ushered in a new era of iOS (for better or worse), and is the biggest visual overhaul to iOS ever. The 5S supports 5 major revisions to iOS, something only the 4S and 5 before it had ever done, and has an opportunity to be the first iPhone ever to support 6 revisions of iOS when iOS 12 is released next year.
6. iPhone 4S
The big marketing push was for Siri, but arguably the most impactful new feature was iCloud. iMessage proved to be an effective retention mechanism for Apple, and iCloud has only grown in importance and moneymaking ability. Siri was the first major digital assistant on the market. While its limitations restrict its impactfulness, it has continued to be a major focus of Apple. The 4S also marked a performance milestone with the first dual-core CPU in an iPhone, leading to its status as the first iPhone to support 5 major revisions of iOS.
7. iPhone 3GS
The first of what would come to be many "S" revisions, this S stood for speed. Where the speed improvements of the 3G stemmed largely from network advancement, the 3GS focused on the phone's internals. RAM was doubled, CPU clock speed increased, and a GPU was added to the SoC. Performance improvements like these would soon lead to the iPhone becoming a mobile gaming powerhouse.
8. iPhone (2G)
The phone that started it all. Though limited in many ways, the original iPhone revolutionized the phone and fundamentally changed how consumers would come to look at cell phones. The all-glass multi-touch display was revolutionary and signaled the end of the BlackBerry era. There were doubters, but the iPhone enhanced user experience in such revolutionary ways that the mobile phone market would never be the same.
9. iPhone 6 / 6 Plus
The iPhone 6 brought a much anticipated change to the form factor, introducing new 4.7" and 5.5" screen sizes. This change brought iPhone into line with the larger market trend of bigger screens and bigger phones, with the Plus model becoming the first iPhone to require two-handed use in most cases. iPhone 6 also introduced Apple Pay, a revolutionary mobile payment system which would quickly be copied by Google and Samsung and which thrust mobile payments into the mainstream. Unfortunately, the iPhone 6 was plagued by issues such as "bendgate" and an underwhelming processor paired with no increase in RAM leading to performance issues. Nevertheless, the 6 introduced the longest lasting design of any iPhone yet.
10. iPhone 7 / 7 Plus
A divisive release, the iPhone 7 is perhaps most notable for removing the 3.5 mm headphone jack. The 7 represented the first numerical (non-S) release not to overhaul the exterior design, with Apple choosing to slightly refine the 6/6S design by adjusting the placement of the much derided antenna lines and releasing a new "Jet Black" color. The 7 did, however, advance the iPhone in some meaningful ways. Most notably, it was the first iPhone to be water-resistant as well as the first to contain a CPU with more than two cores. The physical home button was also replaced with a capacitive version to aid with water resistance.
11. iPhone 8 / 8 Plus
The first iPhone to only have flagship status for about a month and a half and also the first iPhone since the 3G to skip the "S" moniker, the 8 is derogatorily referred to as the 7S by many due to again recycling the same basic design used since the 6. However, the 8 did feature the first glass back on an iPhone since the 4S, this time for the purpose of introducing wireless charging capabilities. Contrary to speculation that Apple was developing its own wireless charging standard, the 8 supports Qi, a standard popularized by Android devices. Apart from this feature, the 8 provided mostly iterative upgrades with further improvements to the CPU and camera technology. The 8 holds an interesting place in iPhone history, as it was introduced alongside what Apple clearly views as its true next-generation product, the iPhone X. It remains to be seen whether the design of the 8 will survive past this generation, as well as what Apple will do with iPhone pricing if the design of the X becomes standard.
12. iPhone SE
6S on the inside, 5S on the outside, the SE was introduced as a direct upgrade for those with no interest in the new, larger screens of iPhones beginning with the 6. The SE was, for a time, the fastest iPhone due to the CPU from the 6S having to push fewer pixels. It would be dethroned in the performance department by the 7, and the status of Apple's 4" device remains unclear. The SE retains a relatively small, but loyal, fanbase.
13. iPhone 5C
Introduced alongside the 5S, the 5C sported the same internals as the 5 before it, but with a new, plastic design. Produced as a result of mounting pressure on Apple to release a "budget" smartphone, the 5C never quite took off and was never replaced or updated. The 5C retains the distinction of offering the most color choices of any iPhone ever.