It has a low FoV and doesn't state the eye relief (which usually means it's naff). I'd imagine the picture won't be the clearest too.
It's not a case of me knowing all the brands and rebrands and knowing what specifically to avoid, but you get what you pay for with tubular optics as a rule. The only people I ever see recommending cheapo ones are those who've never looked down something like a Visionking (who make - relatively speaking - very cheap, yet quite clear and robust optics).
Edit
Here: http://www.dhgate.com/store/product/visionking-3-9x40-rifle-scope-black-matte/387310777.html
Includes shipping, is variable between 3x to 9x, has a good FoV and good quality glass.
Edit 2
As an aside, I should say that - if it bothers you - a rifle scope on something like the G5 almost always looks a bit naff after a while. A lot of people go for the variable short dots that Visionking do as they're quite useful up close, have a clear, illuminated reticule and also go up to 5x for spotting. See here: http://www.dhgate.com/store/product/wholesale-visionking-1-25-5x26-rifle-scope/138138542.html