A little background: I used the Motorola Razr for about 5 years. My first Razr broke in 2007, so I got another, and that one lasted until the beginning of 2012. Now that I bought the Z331, I am astounded that the Razr was superior in many ways, even though it's now 5 years old.
The main problem with the Z331 is there's a noticeable lag with every button you push. Texting is an absolute nightmare. Imagine if you were typing but you couldn't see the words for a full second or two. Sounds harmless enough now, but when you're using this phone every day, it's enough to drive you nuts. It's like it's always a little bit frozen, and can't catch up with what you want it to do.
The messaging center is a mess too. On the Razr, you could see the start of about 8 messages, so it was easier to find the one you wanted. On the Z331, you can only see three. Now if you want to scroll down to find a certain text, that lag problem rears its ugly head and makes it a real hard process. This may seem like annoying nitpicking, but trust me - even if you only send a few texts a day like me, you will become very, very, very frustrated in a few weeks. I'm not a teen that sends a hundred messages a day. If you're looking at this review you probably aren't either. But even if you occasionally text, I'm warning you to stay away from this phone. The worst part is that the Razr, with its 5-year-old technology, was so much quicker and had a better menu system.
That's the biggest gripe. I like the outer display, the large keys, the smooth feel of the phone. Battery lasts a couple days, sound is good. Pictures are easy to take and look crisp enough.
A gripe that others have made before is how these phone developers have sneakily made the center button a connection to the Internet. You'll probably find yourself accidentally pressing that button all the time... especially when there's that button lag, you don't know which menu you will be on when the keys finally register, and you've found yourself paying for an unintended sidetrip to the web.
Overall, I am extremely disappointed with this phone. Yes it's cheap. Yes it's supposed to be a simple flip phone without all the bells and whistles. But when it pales in comparison to 5-year-old technology, in this day and age when there are advances in the field every day, it's unacceptable. My advice: spend the extra money and look for a nicer phone. This one isn't worth it. I'm counting down the months until I can get rid of it.