Basically he says that ICS is a good brand to look for. Not the new clear ones but if you can get your hands on a black one they're great.
They have a "split mechbox" design which basically means that it's a lot easier to take apart and do spring changes and such. People say it's prone to breakage easier and think that no parts are compatible since it's a different design than the "TM" standard (Tokyo Marui basically sets the standard for aftermarket parts and accessories). Anyways, the only parts that aren't compatible on the ICS according to him are 3 parts, everything else will fit.
Also sorry to use advanced language.... A PEQ is basically a LAM unit (Laser Aiming Module). The US Army I believe it is uses a special naming convention to classify the types of accessories they are. For example PEQ if you break it down will have P, E, and Q. I forget the nomenclature but all I know is that P is personal meaning it takes one soldier to carry it rather than 2-3 people (such as a mortar), or having it mounted on a vehicle).
Anyways in airsoft the use is totally different. They're basically just the shell so that your battery can be protected. They will hold your battery, a large I believe and you should be good to go for the day. Essentially instead of rear wiring the battery to the back of the stock on the gun (since there is no room if you use certain types of stocks) what you're doing is making an alternate place to keep your battery (in your PEQ wired to the front.
If you look at KND's gun right underneath his scope and to the left that's a PEQ. If you look closely you can see two wires, what do you think they are? They're wires for the battery of course.
Really it's your choice on what brand and model of gun to get so either look up some reviews and see which looks good for your price range or camp the classifieds for some deals (sometimes you can go a few pages back to see sales that haven't been bumped up yet, it's not just the first page where all the sales are).
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE