Cnet reviews O2 Xda Atom Exec... "On its own, the Exec is a highly impressive, push e-mail enabled smart phone, but if you already own the first Atom, its upgrade worthiness is questionable."
The Exec runs on the familiar Windows Mobile 5.0 operating system, upgraded with the Messaging and Security Feature Pack. Among various security improvements, this provides push e-mail capabilities which, provided you've enabled a data service through your carrier, sends new e-mail messages directly to the device without forcing you to continuously login. This is identical to the service provided by the HP iPAQ rw6828 and similar to the BlackBerry's push e-mail system.
One of our biggest concerns surrounding the Exec was that the faster processor would have a detrimental effect on battery life. However, O2 rates the Exec as having the same battery life as the original Atom: up to 5.5 hours of talk time and 150 hours standby time.
In our Spb Benchmark battery test, which runs the device through constant general usage tasks with the backlight always enabled, the Exec lasted for six hours and twenty minutes. This is a pleasing score; the HP iPAQ rw6828 scored seven hours and three minutes, but this is expected due to its slower 416MHz processor. Under regular, intermittent usage, we went almost four days without needing to reach for the charger.