For the most part, guns you can get from MaoMart and Crappy Tire are very low end. Most have plastic gearboxes and low quality parts, most of which are proprietary (meaning you can't just use a standard AEG part), so when something breaks, it's almost impsooible to repair as parts aren't available. And they will break as they are very low quality in the grand scheme of the airsoft world.
There are some guns available at retail stores that are a decent beginner guns. Kracken AK's and Broxa MP5's make decent beginner guns. If they are gone over by a compitant gundoc, they can be made into a pretty good gun for the money.
Now, if you compare these to Classic Army, Tokyo Marui, ICS, etc. they are junk. The fit, finish and quality of parts and assembly just isn't there. For the extra money you spend to bring the low end stuff up to a higher end level, you may as well have just bought the high end to begin with. JG are ok, they've actually come a long way in a short time. A&K and AGM are decent for th emoney as well, but it's the whole quality thing all over.
Think of it like cars. If all you and your friends ever drove were Lada, Skoda and Trabant, you'd probably think there's nothing wrong with them. They're low cost, simple and do the job. But once you drive a BMW, Mercedes or AUDI, you realize the difference.
Pretty much stay away from and AEG with a plastic gearbox (other than STAR) as they will break in short order and parts are pretty much impossible to get. And remember, you get what you pay for. There's a reason these guns are cheap and it's not because they are made in China.
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