The Archos 70 runs Android 2.2. It's not the latest version of Google's OS, but it is still the newest version that's commonly available. More expensive rivals due out soon will use Android 2.3 Gingerbread or Android 3.0 Honeycomb though.
The difference? Android 2.2 was designed with smartphones in mind, not tablets, where later versions of the OS are made with more awareness of the tablet market. Android 3.0 Honeycomb in particular was made precisely for these mid-size devices.
Evidence of this smartphone mis-match lingers in the Archos 70. Occasionally, notifications will pop up referencing the device as a phone, as if it's having an identity crisis. Archos has done its best to transition Android's gender change from smartphone to tablet, grafting-on a custom user interface. It's very simple, its main aim to make holding the thing in landscape orientation feel right when the vast majority of Android 2.2 gadgets tend to be held upright.
The user interface does this with a thumb-operated side menu that stays on-screen whether you're on a home screen, within the apps menu or in an app. It bows out when a video is displayed full-screen, but it's otherwise a constant companion - a replacement for physical soft keys.
It functions very well, auto-rotating depending on how you hold the Archos 70. As the main component of the user interface, there's not been as radical a change from vanilla Android here - especially in looks - as in many Android smartphones. However, when some manufacturer-made UIs can make Android worse, we inclined to think this minimalist approach is a good thing.
However, in spite of packing a fairly powerful 1GHz ARM Cortex A8 processor, day-to-day navigation isn't lag-free. Android 2.2-powered smartphones with 1GHz processors like the HTC Desire run very fast thanks to the level of optimisation of the OS, and by comparison the Archos 70 seems slightly sluggish. However, it is more responsive than the larger Archos 101.
We talk as folk who have thumbed one-too-many Android devices to be particularly patient with lag though, so if you haven't been similarly spoilt the slight blips and stops of the Archos 70 may not annoy. It's possible that Archos will improve speed with a software update, although updates to most of Archos's devices of the past couple of years have tended to offer minor tweaks rather than anything ground-breaking.