Tapco's Galil mags are great. They're better than the real metal ones, which are almost always worn out and improperly serviced. I have a Golani, and the mag that came with it was completely unusable. I didn't put a bullet guide in my Saiga .223, but my Galil mag locked up just fine in it.
Here's the problem with original Galil mags: their springs are usually worn out, and you can't get replacements. Someone tried refurbishing mine with an AK-47 spring, but the AK mag has a much higher curve, which left the rear of the follower poorly-supported. The end result was that the bolt carrier ran completely over the round without picking it up. Every single time. Put a Tapco mag in to replace it, no problem.