I sell them. I've never had a return with any case i've sold. I had one and loved it but it was for my black iphone4 then I got the white iphone 4 (now i have white iphone 4s) then gave it to my fiance who uses it now and he loves it.
With them not lining up right. I noticed when customer put them on their phone, they're not adjusting the plastic and silicone properly. Very common error.
Everyone is entitled to their own opinion. Some cases you will love and you'll spend 10$ on them. Most of the time you'll spend more money on the one you'll keep and it will hold up the longest. That's why you should always try them on before you buy or verify the return policy before you purchase so you know you can return it without or with little penalty.
The manufacture cannot please everyone. but they do try.