I've been to all 3 of those shops. I've bought from Chigun upstairs and J&J (the really hidden one). I can say this from my experience:
UNLESS YOU KNOW HOW TO DEAL WITH INTERNALS WELL, DON'T BUY GUNS FROM J&J.
Every gun they have that is full metal/non-cansoft (including pistols) is modified. And they don't even use good parts for them, so they break quite easily.
I've had a million problems with my JG G36C, both before and after downgrading it from 430 fps.
I've had two million problems with my Cansoft WE, and half of those didn't even have to do with the plastic frame. (Some might remember my various threads on that)
However, to be fair, they are quite nice, and as some mentioned, sometimes don't know what they are talking about. I often buy parts/mods/accessories from them and not from the other stores because the atmosphere there is much more friendly and less of a "this is a business, so buy or get out". You can also haggle with them sometimes, but they will be quite firm on certain things, like the pistols. In the end though, with good bargaining skills, you can still manage to get it down to something reasonably low.
Upstairs, Chigun is...well...similar, in the sense that there isn't much of a tense/awkward atmosphere (more on that later), but still a little. Some of their stuff is pretty cheap and they've even got full metal/black pistols (I haven't asked if they are modified) for prices which could rival that of the new popular airsoft site (you know, the one who had the M93R Limited, but never restocked on it >_>). You can haggle a little, for instance, I got an EMAG (not Green Label) for $20. They'll be happy to answer all your questions and seem more knowledgeable than the guys at J&J.
As for the DVD store one, both times I went in, I was pretty much greeted with "Can I help you?" and it was sometimes in a rude tone. One time, it was understandable, as I was the only one in the store, but the other time, the store was almost packed and yet, I was singled out (I guess it could be becuase I'm underage, but still). I replied with a simple "Nope. But thanks." I was only in there for 5 minutes (the time I was alone), but already, the atmosphere had turned awkward. I never walked in there again. Although I was tempted by the MP7 they had on display.
I end up giving most of my business to J&J in the end because I find that I can check things out without being hassled or given suspicious glances at and the fact that they have samples/floor models of most of their products (apart from their rifles).
Enough with my rant/$0.05. This has probably been my longest post yet. Sigh....
EDIT: I just realized that my post was completely off topic.
About Asia Electric Guns, I don't have any experience with their guns, but I can that their mags are of average quality, being compared to one of TM make.
VFC Saber SD Urban Grey - VFC SCAR-L Tan - KWA MP7 Tan
WIP: Magpul FPG Conversion to TM Specs (currently KWA Spec)
Last edited by Freeze; June 28th, 2012 at 16:11..