I've got to chime in here even though I wasn't asked, lol. My perspective comes from a person who knows nothing about how to use an iphone or ipad and has no intention of buying one, I am just an investor.
1. Apple isn't and shouldn't be concerned with concerned with iphone as far as the perspective of leading in market share. What's important for apple in the segment are: 1. margins and 2. Sales growth over seas. When you pay Verizon $200 to upgrade to your iphone5 or whatever apple not only gets the $200 you paid but also another $400-$600 from the phone carrier. The concerns here would be carriers not paying their costs on the phone vs the much cheaper fees they pay to Samsung, Nokia, etc... on their phones. The other concern would be that people in developing markets would not see the value in paying a premium for an apple product over another brand.
2. As far as tablet growth I do not see the market as being over saturated at all yet, especially not overseas. The danger here in my opinion comes from the new generation of Windows 8 machines that can be true desktop replacements in the form of a tablet, but even these haven't proven themselves to be widely accepted yet.
3. I know that no Aapl product has better specs than any other brand out there for a cheaper price. Aapl's secret to success has been making products that are easy for stupid people to use. Products that "feel" good and that make technology less intimidating.
Something that you need to realize is that the earnings miss they just had wasn't a "bad" earnings result. They grew by 19%, which is huge, compared to the 20% that "analysts" had guessed they would make.
I think the real reason for the selloff in the past few months is 2 reasons: 1. Aapl was very very over owned by both individual investors but mainly by funds and a correction was due. 2. Aapl went up so much in 2012 that a lot of the selling was simply people taking their profits.
In this short term owning Aapl is going to be like living on a roller coaster, but the long-term investor should see this sale as a buying opportunity.