so i haven't read any of this, but on big shot bikes:

one came into the shop needing an overhaul. headset was shot, about on par with walmart bikes, bb was pretty bad as well. mostly looked at the wheels though as the customer wanted them tensioned and trued.

first up, the wheelset was about 4kg, or almost 9lbs. now to be fair the tires and tubes were still installed, but even with those off the wheelset would still be around 2800g, well over 6lbs. they were built with quando hubs, which i haven't seen in forever due to their low quality and relative cheap price nowadays of sealed bearing formulas. wheels were all sorts of out of true and impossible to get perfectly straight. the owner hadn't put many miles on the bike (maybe a couple hundred)

i'd stay far, far away. somehow i think even a republic bike would be better (though don't read into that as a recommendation for a republic, but rather a reason to not consider a big shot at all)

If you have a decent lbs around you, i'd go in and talk to them about your budget. you'll spend more up front, but they should be able to set you up with something for $450-500 out the door (check out the smaller guys, the one i go to usually orders redline or torkers for budget-minded shoppers. the torker u-district is around $350-400+tax). figure that if you get a bike online, you risk getting the wrong size, damage in shipping, and improper assembly that may lead to broken parts. if you're mechanically inclined assembling a bike is super simple, especially a single speed. if you're not then you'll be paying an extra $75 to have a local shop assemble it for you.