Many times I notice nobody call me, so when I check the cell phone was off, our of battery, I really regret buying this, but at least is useful for simple phone calls

I used to like MS products, but this time I was disappointed

the biggest problem is voice disconnections every time and no clarity

She even recommended valid "quiet time" settings, based on the time I charge my phone each night.

Cortana (the personal assistant) works well, is improving all the time and has proven to be quite useful

However, If you were disappointed with the loading... times on the 521, you'll be pleasantly surprised with the 635

But the facebook app stinks - dumbed down - and the apps and internet browser close suddenly all the time on me

Not worth your time and effort

Cortana gets auto launched at the worst times

Pretty durable, I drop it all the time with no case on it, but the screen does scratch pretty easy.

I thought I'd miss the apps from Google play store or iOS store but really apps just take up your precious time when there is more things to take in

If you want more bells and whistles, pay more!!EDIT: I need to note, this phone has frozen three times in the month since I got it

It has all the features I liked about the 521 and the same handy T-Mobile/Nokia built-in apps (Cortana, T-mobile wifi calling, Here Maps/Drive with offline GPS) but is noticeably faster, has a more attractive design and larger screen, and has LTE capability

My cell phone is inherently prone to irreparable damage... slips out of my hand as I fumble for my car keys... slips off the bathroom sink and into my toilet