Ok, so My current M4 Mags are five years old, jamming constantly, splitting at the seams, and in general tore up. So I need to find some new replacements. So far I have narrowed the search down to two contenders.
For clarity, this is my current M4.
Internals:
KWA Base Model
Magnesium 8mm gearbox
KWA magnesium gears and piston
8mm ceramic bearings
Madbull 6.02 gen2 tightbore
Extreme-fire SW-CHEETAH Mosfet 3rd/burst
Two 11.1v 1200Mah LiPo Sticks in the stock
Deans Connectors
Externals:
KWA battery butt stock
MagPul front RIS
King Arms Pistol grip
JBU M4 KURZ Silencer
Tatical Bipod grip
PEQ-15 with Green Laser
Aimpoint 3x magnifier with Colt Arms QD riser
Aimpoint Mini T-1 red/green dot with Larue QD riser
Streamlight TLR-2 QD red laser/light
Not totally crappy paint job.


Choice one, The KWA Midcap box of 8: $50.00
http://www.airsoftpost.com/product_info.php?cPath=23_56_429&products_id=27779
Quote:
MAG 130 rd Midcap Magazine for M4 / M16 Series Airsoft AEG (Box Set of 8) - Tan
Capacity: 130 rounds+20 (Triple stack design, may require loading and unloading a few times with silicon oil to "break in" a new mid-cap magazine for best performance.)
Features:
- Great precision feeding.
- Light weight. Designed for you to carry tons providing you with gaming experience you can't find with hi-cap magazines.
Review: If you are shopping for a mid-cap for your KWA M4, MAG is the most compatible out there. Great feeding in Marui, Classic Army, G&P, G&G, JG, Echo1 and other M4 / M16 series Airsoft AEG Rifles. One of the most popular Mid-CAP magazines out there for M4 series.
Pros:
1- more ammo per mag
2- stated that these are "the best" for a KWA
3- Cost is cheap for 8
Cons:
1- Cheaply made, questionable durability
2- Triple stacked bbs. I have issues with feeding on double stacked mags, I can only reason that triple stacking would be potentially worse.
Choice Two, The PMAG box of 10: $88.00
http://www.airsoftpost.com/product_info.php?products_id=30207

Quote:
Magpul 75rd PTS PMAG for M4 / M16 Series Airsoft AEG - Flat Dark Earth . (Box Set of 10)
DESCRIPTION:
The PMAG™ (Polymer Magazine) is a lightweight 75-round 5.56 NATO, M-16 compatible magazine. This PMAG™ features a straight body and pop-off storage/dust cover that alleviates pressure from the magazine feed lips, allowing for long-term storage of loaded magazines without risk of feed lip creep that often causes malfunction in standard aluminum magazines. PMAG™ utilizes a resilient stainless steel spring for corrosion resistance and a controlled-tilt, self-lubricating follower for increased reliability.
Pros:
1- Better grade of plastic, potentially highly durable
2- Single stacking, reliable BB feeding.
3- Not as easily stolen and fielded as most people don't use PMAGs yet.
Cons:
1- Price is more
2- Less rounds per Mag
3- ....There was one more i had thought of, but i can't seem to remember now.
So there you have it. I would like your opinions on the choices, the Good/Bad/Ugly/And Alternatives.
And just for the record, I only state that the round count in the mag is a pro or con because many people view it that way. I know that if I can't hit what I'm aiming at with 75rds, I should probably be put in some form of remedial weapon and tactics training.