Wrong? Not necessarily. I have heard the stories too. I believe there is some validity. It depends on which magazines you are using. For that matter, some 7-rounders are pretty bad. I shoot at least once a week with a small group of very experienced 1911 pistoleros at a private range. Each of us burns 300-500 rounds of .45ACP per session. There are a lot of Kimbers in this group and 2 or 3 of us are really into Custom Colts. We are continually comparing accessories such as holsters, sights, triggers, ammo, and magazines. A couple of the guys switched to 7-round MetalForm magazines (the ones with the welded base) on the advice of Mr. Alex Hamilton, one of the best 1911 pistolsmiths in the country. Alex says these mags are unsurpassed in function and reliability.
Personally, I only use Chip McCormick stainless steel 8-round mags for practice and daily carry. Why? Because they work for me. When I practice, I take 8-10 to the range. I need at least 6 and someone always needs to borrow a couple.
I've been using the same mags for practice for about 3 years. They've been dropped on a hard floor during combat reloads dozens of times, even stepped on.
I keep 4 in reserve for daily carry (I carry 2 and rotate them with the other 2 each month). I don't shoot with these as often as I do with the practice mags. When I buy new ones, they replace the carry mags which are then moved to the range bag.
Bear in mind, sooner or later any mag will decide to go south. In the past 10 years I have thrown 5 mags in the trash bin: one 7-round Pachmayr (junk), two 7-round Colt (average), and two 8-round Wilson (good). Still using the first McCormicks I bought 4 years ago. Every .45 mag I have ever owned was/is stainless steel. And I'm a happy guy.
Best regards,
tawakoni