The Moto 360 is a great looking device and is easily the prettiest smartwatch we've seen to date. However, one theme has come up in early reviews of the device that should give anyone preparing to shell out $250 for it pause: It apparently has subpar battery life.

FROM EARLIER: Motorola's gorgeous Moto 360 smartwatch goes on sale today at noon

Two early reviews of the device, from The Wall Street Journal and The Verge, both call out the Moto 360's battery life as a significant problem.

"Even this big, honking model had to be charged twice a day," writes the Journal's Joanna Stern "Most days, after charging it overnight, I had to put it back on its wireless charging cradle by 4 p.m. If only the large black circle could also work as a sundial so I could still tell the time when the battery dies."

"Motorola says the 360's battery lasts a day, but I haven't seen it last that long yet," writes The Verge's David Pierce. "I don't expect a smartwatch to last weeks or years, but it ought to be able to last a day and a night no matter how much I use it. My watch now dies before my phone does, and that's unacceptable."

Because smartwatches are such a new technology, companies are still struggling to figure out what tradeoffs are necessary to optimize the user experience. This is particularly tricky with smartwatches because they can't be too big or they'll look silly on your wrist but they can't be too small either because they need to be mobile computers as well.

None of this means you shouldn't buy the Moto 360 but if you value a device that delivers really good battery life then it's certainly something to think about.