As expected, the iPhone 5 sells in huge numbers during the June 2013 quarter but will it be an automatic jump to the iPhone 5S on release date? There are strong signs that the iPhone 4S remains a formidable rival within.

Released two years ago, the 3.5-inch 4S is now considered a legacy Apple handset but the 2011 flagship is still a hot merchandise, according to AllThingsD, so hot that it takes away considerable sales numbers from the 4-inch iPhone 5.

Citing data from Consumer Intelligence Research Partners, the blog site reported that the 4S came in a close second to the iPhone 5 by securing 30 per cent of the total smartphone sales that Apple has garnered from April through the end of June 2013.

The iPhone 5 clocked 52 per cent, which suggests that after some 24 months from its debut, the iPhone 4S still commands a huge following among the iOS crowd. Below are two reasons why the device remains popular and why it promises to be a better buy than the upcoming iPhone 5S.

A solid tag price at $99 or lower

No doubt the iPhone 5 is more powerful than the 4S and so is the 5S. However, it doesn't follow that the former Apple headliner is less capable since the first two share iOS 6. For many buyers it is the features that matter and not the top-notch components that they don't actually see.

That's why the 4S is flying off the shelves in great numbers until now - it performs, it delivers and it is a gorgeous device to own. The latter is easy to do at this time as most distributors and retailers offer the handset for only $99 or even less, depending on existing promos and services packages. On T-Mobile, for example, the 4S can be had for only $70, which is a downright bargain for anyone.

A solid platform thanks to iOS 7

Apple introduced Siri via the iPhone 4S and the tech giant is continually improving not only the digital assistant but also the whole killer features menu that come with the iOS platform. June this year, the company unveiled a simpler and updated iOS 7, teeming with power features that will make the iPhone 5S more exciting.

All these bump ups, according to Gotta Be Mobile, will be absorbed by the 4S come September this year, which is the same time that the iPhone 5S and the iPhone Lite will be launched. The handsets will showcase a better Siri and all the other iOS 7 enhancements, which will also be ported to the iPhone 4S.

The upgrade will bring the 4S in almost equal terms with the two generations of iOS devices immediately following it. That should make the iPhone 4S more irresistible for buyers who wish experience the new iOS 7 environment but are unwilling to pay too much cash - this despite the imposing presence of both the iPhone 5 and iPhone 5S.