Just a friendly reminder in this post: when you're doing responsive design, you need to think about all devices, not just the ones that you immediately use or the ones that you think are most popular (especially without actual data). In particular, this one goes out to all my design comrades in the business. Don't get too obsessed with making a perfect experience for your Apple devices that you're so fond of.
Designers have had a long history with Apple and their products, since the Apple 2 in the 80's. Most designers still use and prefer their Apple devices to work on. Many learn their trade on Apple computers. Unfortunately, designers of all kinds are only human. We tend to think about our own little bubble and believe that many people also occupy the same space and therefore, make our experiences accordingly. However, in this time of rapidly evolving design techniques and the plethora of devices that can (and will) access the web, it is a foolish thing to do.
Think Outside of the iBox
I'd refer to the term of the "zombie apocalypse of devices" that are on the way. Connected devices of all sorts are coming. Watches, phones, fridges, cars, glasses, televisions, game systems, washing machines... and those are just the ones off the top of my head.
If the point of responsive design is to make an experience for as many devices as possible, and to future proof your site to them as best as possible, then iOS devices are a very small piece of that experience. That percentage may also be getting smaller as new devices come out. Not to mention, Apple's lines are evolving all the time as well. What happens when you made a special experience for iOS devices only to have that experience break on new Apple devices? While Apple does take some care for developers in this regard, it isn't a guarantee they always will.
I also mentioned in a previous post another reason to not specialize for particular devices in responsive design. Users can and do take notice of differences in experience between device types. If I'm on a device other than iOS and someone else who is on iOS gets something special or an interface that works better than the one I'm served, as a user I am immediately turned off by your site. You've shown a preference towards a particular audience that isn't me. In the case of a business, I may decide to just take mine elsewhere. Are you willing to alienate certain user bases because of their choice in device? That attitude reminds me of the "You need Internet Explorer to view this page" days. I would hope we're beyond that.
You should also be asking that if a design decision is better for iOS, why just give it to those devices? Maybe it is worth considering putting it across all platforms as well.
By specializing for particular device types, you're also making more work for yourself for those specific devices. Why not just give everyone who met certain criteria the better design solution using progressive enhancement?
As designers we need to make sure we consider all the angles when building a site. If we're building for the future, then we need to show it. While iOS and Apple are undoubtedly part of that future, it isn't the only player in the game. This post is mostly about us paying to much attention to iOS and Apple products, but it really goes for any device type. Don't fall into the trap of thinking everyone or most people are using the same thing and specializing for it. It has chance of biting you later on.