I have a feeling your source is confusing the Liftmaster with the Wayne Dalton which is surely a piece of junk.

An opener should never see a heavy door. The door is counter balanced by the springs and if it is properly installed and maintained a small child can open it. This shouldn't be a factor in your decision at all.

That was the first thing I asked. He said no, he was talking about the Liftmaster brand, not the Wayne Dalton I-Drive, or whatever they call it.

When the Liftmaster 3800 first came out there were a number of problems. It seems now that most of these idosyncrasies' have been worked out. I am the service manager for one of the larger garage door companies and I don't get near the calls now as I did a year ago. Also, we do not install them in doors over 14' high.
Alexis

Thanks Alexis. That's very useful information.

I agree.
We install the RJO all the time and never have any problems.
To be honest, I am still in awe every time we install one.
They are incredibly well designed and made and give us no problems at all.
You will be happy with it.