I have mixed feelings on the issue, and I see valid points to both sides. If nothing else, certainly feel that the LCM as a whole is treading in dangerous waters.
The whole idea that they have a distinction between the "low gospel" and the "high gospel" is a big red flag to me. Also, as
Terry mentioned, the practice of trying to determine who is the "good material" is contrary to the gospel that Jesus taught and has always been a bit disturbing to me.
The reason that I don't say with certainty that I think the LC teaches another gospel, is because I believe at heart those in the LC are willing to teach the basic gospel to an unbeliever. A lot of what goes on seems situation dependent.
I was involved once in a home meeting that didn't have any of the "good material" type, and that was a positive experience. There were several who were brought to the Lord in that through that home meeting.
With some of the campus work activities that I was involved in, I saw a number of examples of exclusiveness that served as proof in my mind that they weren't concerned with just teaching just the gospel. There were politics at play. There were not-so-hidden agendas that were being carried out. I have mentioned how I was at Bible studies where brothers used the time to try to get newcomers to use the RcV Bible, and it wasn't always clear if some of these newcomers were even saved. Why wasn't this time used to introduce them to the gospel instead?
Another situation I recall is when a college-aged boyfriend/girlfriend couple came to a meeting and out of the blue a brother told them they were best off "dropping the relationship" so they could focus their hearts on the Lord. They never came back

. Anyways, from what I've seen, many opportunities where the gospel could have been preached we're ruined by these ideas that other things were necessary, like getting people to use a certain Bible or meddling in someones private life. I don't know how common some of these notions are, but I've seen enough indication that there are many in the LC who are not satisfied with simply introducing someone to the gospel.