With a current Sony A580 price at around £650, it goes up against Nikon's D5000 and Canon's EOS 550D. In terms of specifications it presents a number of benefits over the former, with almost 4MP extra on its sensor, full HD recording, a faster burst rate and a larger, higher-resolution LCD screen.
Based on similar criteria the A580 arguably comes up a little short next to the EOS 550D, whose 18MP sensor and (slightly) more detailed LCD screen may be preferable, although its burst speed and fixed LCD may not be.
With regards to operation, the EOS 550D offers a similar set of controls on its rear to the Alpha 580, while the D5000 maintains the Nikon style of a column of buttons to the left of the LCD, and just a few around the rest of the camera. Which way is 'best' is down to personal preference, although direct access to controls is perhaps easiest on the Canon, with the Nikon and Sony requiring many changes to be made through each camera's respective graphic user interface.
The Sony A580 body is also both the bulkiest and weightiest of the three offerings, particularly when compared with the Canon EOS 550D. A heavier camera isn't always necessarily a disadvantage, however, as it can help to balance longer lenses. Plus, with image stabilisation incorporated in the Sony A580 body, it's worth bearing in mind that Sony's lenses don't require the extra size, weight or premium of image-stabilised lenses.
In addition to rival manufacturer's offerings, the Sony A580 also faces competition from its A560 launch partner, whose only real difference is its 14.2MP sensor, and there will also be competition between the Sony A580 vs A55 and A33 SLT models.
As the Sony A560 release is due in the coming months, it remains to be seen how much cheaper it will be against the Sony A580 price, although for those not needing the extra 2MP it may prove to be the more tempting proposition.