The looks:
Well compared to it's real steel brother its extremely well Made, the lower frame is a little shiny but compared to the other Glocks not made by KSC it's a whole lot better, and there's a small crease going down the middle of the lower frame but that dose not bother me much(see picture below for the crease).
KSC has replicated every thing all the way down to the serial number underneath the lower frame,
and the Glock markings on the grip, slide, and bottom of the mag, and the replicated 9X19 on the chamber cover. The metal slide is a must have for the Glock 18c owners because if you don't have a metal slide you can't use top gas (if you use top gas with the stock slide it will wear your slide notch away really fast), the down side is you can't really use the HFC134 with the metal slide it really can't get enough power to work right. But the metal slide is worth it, you get a nice ca-chink with it, you also get increased blow back. Also though with the metal barrel the top of the chamber cover the finish will wear off not really a big deal.
You can buy the metal slide at www.tacticalair.com for around $80 or $90 I think or if you want you can get the Glock 18c with metal slide and outer barrel and High flow internals for $235 at www.airsoftextreme.com Which is a really good deal. The metal parts consist of the Slide (Note I am reviewing the upgraded glock not standard), outer barrel, inner barrel, guide rod, all internal parts but blowback piece, clip, and all internals on the lower grip. To take the gun down (take it apart)
you just put the selector switch in the middle position and pull the slide release buttons on the side (right over top the trigger) down and pull the slide back and then forward and the slide will come right off. Just a note I always store my glock with the trigger decocked. Now you are probably wondering about the decocker, your probably saying to your self where is it, well there is non, the only way to decock the gun is to pull the clip out and pull the trigger, and to recock it just pull the slide back. All in all this is a Kick ass gun. Oh and I almost forgot, this is exactly the size of the Glock 17 so you can put it in many real steel holsters
(I got a Fobus tactical holster check them out Fobus).<
Well now your probably saying enough of what it looks like tell me how it performs:
Well when I first got it in the mail I
immediately put gas in it and fired it off, I just Got to say "THIS IS A KICK ASS GUN," it has about a kick of a .22 and it's pretty loud it has a sound of a suppressed .22, it has enough sound to echo when I shoot it out side and on auto it kicks hard (for an Airsoft gun anyway). Well when I first got it I did not car about the hop up but a few days later I adjusted it, it proved to be a good gun, I can get about a 2+/- inch group at 20', If you practiced every day you could probably pull off a 1" or smaller group, which is pretty good 
(there is a picture of the test I conducted at the bottom) for a pistol this small. You can easily hit a man-sized target at 75 feet. Now I'm going to talk about the selector switch, when it is in the up position it is in semi, when it is in the down position it's in auto, and when it's in the midle position it's on safe, since there is no really great safety’s this is the best of the three. The other safety’s include the trigger one, there's a little button in the center of the trigger and the trigger can't be pressed in less this is first pressed and you can also take your finger nail and pull the button out and it brace's against the back of the grip and then the trigger can not be pressed at all (personally I think the last safety is a waist of time). Next up the speed, well All I can say is WOW, the slide moves around 10 full cycles a second so you can empty the standard clip in about two
seconds (the standard clip is 23 rounds), you can also get the high cap clip that holds 49 rounds and it take's about 4 1/2 to 5 seconds to empty that, and there is no cool down effects with the Top gas with both clips which is awesome(cool down is where the clip gets cold and the speed of the slide and the speed of the BB slows down a lot).
Now the Clip:Well I'm doing every thing out of order but this is my first review I wrote so give me a little slack, any way the clip has a slide away but that covers the valve stem which I like because it looks more authentic in a holster, and protechs the valve. All you do to fill it with gas is pull the button on the front down and slide the but off and fill it. To load it with BB's just pull the view loader button down on the front and
it will lock and you just put the BB's in, and after your all done puting the BB's in just push the button and your ready to go. The upgraded glock you can only get about 1 and a half clips on one fill, as of the standard one you could probably get at least two clips worth on one fill (I'm guessing of corse).
NEW UPDATE:
Here's the long and short range test I conducted, the short range is at 20 feet, the long range was at 50 feet (only got 8 shots on for the long range test but not bad considering the target was only 8" by 8" and the wind was blowing). The Glock has a habit of shooting a little to the left which can't really be fix because the site's are non ajustable but all in all not bad. But don't take my word for it check out the target for your selfHere
Conclusion: WOW I just can't say WOW enough KSC really pulled it out on this one this time. Well if you don't have $250 to get the upgraded version of the Glock 18C then buy the standard one, you can always upgrade later. I would suggest this gun to anyone it's reliable it's fast, accurate and small It's defiantly worth the money.
NEW INFORMATION (june 9th):
Recntly on my glock 18c, the pin that holds the selector switch on seems to be falling out allot. When I figure out a fix for it I'll post it. I might be able to use some lock tight, but I don't know. I'll let you all know at some point.
Well ya all I found out the problem why the pin kept falling out, it was due to a little allen screw under the rear site, it must of came loose from all the full auto firing.
also recently part #10(witch is the loading ramp piece on the bottom of the barrel) broke on the side surprisingly it still works but now you can get a metal replacement at DenTrinity.com for $25 witch will replace the stock plastic one.
"REVIEW BY BACKLASH"