I rarely use Homeline, so I can't speak specifically about the brand. What I can say, in general terms is that you generally get what you pay for, but you already know that. Also, many companies that made top quality electrical equipment decided not to ignore the market for lower priced equipment and their lower priced offerings are a pale imitation of the top of the line equipment, which basically means the same thing as my first comment.

There is another possibility, Square D may have produced a bad run of panels. You might check their website to see if there are any recalls and while you're there, get their contact info & drop them an e-mail outlining your problems.

I use Homeline a lot, primarily because I like the layout better than on the QOs. It has been my experience that the issues you refer to are installation issues, not quality issues. Too much torque on the main lugs can crack the plastic, or not enough can cause the wires to loosen and excessive heat melt the plastic. A broken holddown tab on the breaker is 99% of the time poor seating of the breaker and forcing it into place.
I have 100s out there, from service combo panels to 6 space subpanels, and have never notice a quality issue.

Thanks for your posts. I've decided to NEVER install another breaker box or subpanel again. I'm almost positive that the electricians that installed our main panel didn't have any kind of torquing device, but I guess they know just how tight it needs to be. Here's some more information that I don't think I mentioned earlier. When I tried to install the tandem breakers, I had a really hard time getting them to fit properly. I had to put all of my weight on it to get it to seat. However, the regular breakers were really easy to install. So, by getting rid of the tandems, I don't have to worry about that problem any more. With the subpanel's lugs, I just tighten them until they feel tight. I would not have installed this subpanel if I had known of the issue of torquing. I used this DIY electrical book that I bought at a hardware store, and it mentioned nothing about torquing a subpanel. It just said to screw the wires to the correct lugs using a regular screwdriver. The only place it talks about torquing is at the meter. Since this, I installed 10 awg wire, so I would assume that an improperly torqued 10 awg wire would put a lot less stress on the plastic than 6 awg wire. If you think about it though, if you have the tension of 6 awg wire versus the little bit of plastic that the screw is in, it would seem to me that the wire is going to win, especially if you used 2 awg wire. Hopefully, I won't encounter any problems in the future.

When you wrote " if you have the tension of 6 awg wire versus the little bit of plastic that the screw is in, it would seem to me that the wire is going to win, especially if you used 2 awg wire.", you revealed a potential source of your trouble.

With rare exception, lugs are not designed to resist the stress imposed by an improperly dressed wire; in other words the wire should be cut and routed such that it will tend to remain in the lug before the set screw is torqued. Sometimes it is not possible to get this ideal situation, but at any rate, there should not be substantial mechanical stress on the lug after the wire is in place. I have seen people use one hand to force a wire in the lug, the other to tighten it up and then say it is good. That method is fast, but the tension imposed by large or too short wires can and will sometimes break things.

Yeah, after this happened, a friend of mine came over and he thought the 6 awg wire was bent too far and was too long placing too much pressure on the lug. He cut out about 4 inches of wire and then bent it so it rested right into the lug instead of forcing it in. The 6 awg wire had previously come into the box and went way out and then came back towards the lug, which left a lot of spring tension in the wire. When I changed to 10 awg wire and 30 amp service, I tried to avoid having very much excess wire and bent and twisted the 10 awg as much as possible to loosen it up and then bent it at just the right angle for it to rest in the lug instead of having to force it in. I remember that when I did this, there was still some tension in the wire even after working with it for a long time to try and eliminate most of this. I eventually put it in and screwed it down and tried to leave it alone.

Can home line sub panels be used commercially?

Sure. However, they lack some features you might need in a commercial installation (such was a 3 phase version).

"I don't have a torque screwdriver and from what I understand, 95% of electricians don't use them either."

Use a torque wrench (inch-pound) with an adapter to 1/4 inch hex bits (this is a pretty standard size for 'screwdriver tips').
As long as you do not do anything to increase the lever arm a torque wrench works just fine, and are easier to find.

You can stack up all the sockets and adapters you need.

Most of the torques for electrical connections are surprisingly high.

You are trying to make a gas tight connection for long term reliability and resistance to corrosion.

Using a torque wrench makes getting the required torque a little easier than a screwdriver.

Wiha makes a complete line of small torque wrenches. Insulated models will be available next month.

A friend of mine told me of a study done on the ability of people to measure torques without a torque wrench. People who had assembled modern furniture were the test subjects. With one exception, every person was over or under by more than 50%. The exception was a man who overhauled small internal combustion engines as a hobby.

If an electrical device has a torque specified in the instructions, and the proper torque is not used, any UL approval is void.

Here is a link that might be useful: Wiha torque wrenches.

"...any UL approval is void."

It is not NEC compliant if you do not follow the manufactures instructions.

"Insulated models will be available next month. "

Who the hell plans on torquing hot fasteners?

It take a lot more than just an insulated tool.

It take a lot more than just an insulated tool.
I've been called an insulated tool on more than one occasion :)

The torquing doesn't scare me as much as trying to cut, strip, bend, and insert into the lugs that feeder cable while it's hot.

Hopefully the idea is that you could check the torque of an energized connection that is already made.

Aluminum tends to come flow enough that it can often use an additional check after a few thermal cycles, even in completely enclosed mechanical lugs.

The bigger issue is making sure the insulation on any tool is still adequate.
Gloves and such have the same problem, but at least are supposed to get tested.

What voltage rating is the tool insulation specified for?

How is its reliability to be determined after it gets a few nicks from use?

The specs for the Wiha insulated torque wrenches:

Here is a link that might be useful: Insulated TorqueVario-S Series

Well, you learned something here -and you should have edited your first post to indicate that.

Electrical work is about 10% knowledge and 90% technique. In the failures that I fix, it's rarely because someone did something electrically "wrong" -it's because they did it badly.

There is a reason that even a trained apprentice doesn't just go and install a panel without direct coaching *throughout* the installation process from a supervisor. Several times. Sigh.

I don't use Homeline products because they are inferior, but -as people here have hopefully learned- knowing how to loop and install feeders (or any electrical device) is more important than brand.