Paul is right, both have their pros and cons.
When I bought my 10" GSO (a year ago), I ended up getting it from Bintel because at that time, Bintel matched Andrews price for me - it was before the "premium" models and before the price drop of about 6-8 months ago. Hey, maybe I can claim credit for starting the GSO dob plague!?
I agree that star-testing (and collimating to an extent) could prove redundant by the time it's shipped to your house - you STILL need to learn how to collimate, regardless of who you get it from. However the squaring of the focuser and positioning of the secondary should only need to be done once, and if Bintel do that then it could be worth the extra money if you're not confident of tinkering yourself.
I also think it would be worth it if the shops started doing things like checking for astigmatism on these GSO dobs, checking for pinching of the primary and secondary mirrors. For some people, it might be worth paying a little extra for it, and it could mean the difference between great views and good views on the first night out.