However, while the two firms may be bitter rivals, both handsets managed to win us over when we reviewed them, each scoring four out of five
The iPhone 5 arrived just weeks ago with a 4in Retina display, an upgraded processor chip and a slimmer rectangular design. At its launch it was faced with the Galaxy S3 with its own 4.8in touchscreen, quad-core chip and a more ergonomic design.
We've pitted the two smartphones head to head to see which one really comes out on top.
On paper, both the iPhone 5 and the Galaxy S3 are very thin, measuring just 7.6mm and 8.6mm thick, respectively. However, Apple has it clearly has taken aggressive measures to ensure that the iPhone 5 is thinner than its Samsung rival.
This means that the iPhone 5 feels quite lightweight in the hand, almost as though it's an empty shell without any of the internal components Apple has stuffed inside.
In fact, the handset weighs only 112g compared to the Galaxy S3's weight of 133g. That makes the iPhone 5 also the lightest.
However, that's not to say that the iPhone 5 is the easier of the two handsets to hold. Thanks to the fact that Samsung has concentrated on designing the Galaxy S3 to fit the palm of the hand, it does just that.
It might be larger than the iPhone 5, but due to the angular body and harsh corners of the iPhone 5, we found the Galaxy S3 much more comfortable to hold and use, even if we did struggle to reach apps at the top of the 4.8in screen when using it one handed.
However, as we pointed out in our Apple iPhone 4S vs Samsung Galaxy S3 review, the Galaxy S3 might feel nice in the hand, but we don't think it feels worth £500 due to its entirely plastic chassis.
Saying that, while the iPhone 4S won this round in our previous head-to-head, the iPhone 5 feels much cheaper than its predecessor, due to its lack of glass-coated rear and feather light weight, which makes the handset feel like a toy.
However, the handset's aluminium backplate still gives the impression of a high quality device, so we don't begrudge the £530 price tag too much.
Winner: iPhone 5