If you've never used anything similar (but branded) you'll think it's fine, a bit clunky, but fine. The second you use anything decent you'll realise just how bad these are.
At the moment the most expensive part of these type of phones are the screens, so that is where savings are made, they're not as bright, definitely not as clear and the delay in response between you pressing the screen and the phone doing anything will become annoying.
You'll never be able to get parts for it if anything goes wrong, and no one will make cases specifically for it.
As a budget item, they do a job, but for the £140 it's selling at I would get a (second hand) Samsung S3