Velocity Arms AK Mags
 

I was wondering if these are any good?

http://torontoairsoft.com/product.php?id_product=1393

I would also like to know if they are compatible with an Cybergun/CYMA AKS-47U?

Also how compatible are MAG AK74 mags with the same gun?

I use the G&P AK-74 mags they are the best feeding mags I have used with my cyma aks-74u. I even used them with a 11.1v lipo and they keep up fine. http://torontoairsoft.com/product.php?id_product=1099

Those look to be rebranded CYMA 150rd metal midcaps.

If you're going for authenticity, you'll want to use AK74 mags with that 74U. Otherwise, any airsoft AK47 or Ak74 mag will fit.

Not to be a downer or anything but I have 5 of those for my M4 and they're garbage. They don't feed properly and jam every 8-10 bbs fired. Waste of $75 if you ask me. Save some more money and buy a more reputable brand of magazine.