Motorola Moto G
Any phone, regardless of operating system, entering the budget market has to be willing to go up against Motorola's excellent handset.
It arrives toting the latest Android 4.4 KitKat incarnation of Google's OS and a 1280x720p display with a 329ppi. And all for an 8GB price tag of £135.
Unfortunately, the Lumia 520 really struggles to compete here. The Moto G boasts more apps, a nicer screen and, if I'm honest, a better build quality. The Lumia 520 can't fall back on its colourful cases because the Moto G sports a nicely rubberised rear plate in a variety of different colours. It's water resistant as well.
Of course, if you don't want to move to Android, then the Lumia 520 is still your best value-for-money Windows Phone 8 offering.
You'll get Microsoft's social network integration and Xbox apps as well as Nokia's exclusive apps like MixRadio and HERE Drive – although that's not to say there aren't decent alternatives on the Google Play store.
While we like the Lumia 520, and the Lumia Black update adds some nice touches, I still don't think it has the ability to unseat the Moto G as the reigning phone of the budget market.
Nokia Lumia 625
Rather than going up against the Motorola Moto G, a much closer comparison can be made against Nokia's new mid-market handset.
Although it costs more – coming in at around £200 – there are a couple of extra features that have been passed over for the Lumia 520.
The Lumia 625 has 4G support as standard. That might not be much of a selling point at the moment, but it becomes more important as 4G increases its uptake.
However, you might be surprised to learn that although the 625 boasts a larger 4.7-inch screen, it still only supports the same 800 x 480 resolution as the Lumia 520. This means that while it's better for tapping out texts and emails, it's not necessarily crisper when it comes to watching media.
The design remains colourfully Lumia, but Nokia has curved the corners on the 625. The slightly larger chassis hasn't led Nokia to increase the storage and it boasts the same 8GB native option as the Lumia 520.
It comes down to value, and whether you plan on using 4G, when deciding between these two. But for our money, the Lumia 520 nudges it. The Lumia 520 has all the core features of the 625 (they have the same RAM also) but remains more wallet-friendly.