Size doesn't matter, unless it stretches my screen

But your fine, lol
As far as stock choice goes I think it was a great choice

The colors complement it rather nicely, along with the effects you have placed such as c4ds and what not

Overall I really like the tag, but the blue/ grey colors seem a little overpowering

There aren't really any quality issues as far as effects or focal go, and I like that you blended the background, giving the sig some depth. The tag also has a nice flow to it. Overall not bad, tad big, but I'm blind, so that doesn't matter anyway
Curious, do you know the rule of thirds?