Combat trim can come in nifty if you use it right. For instance, from going into low-speed configuration to sudden power dives, you can quickly toggle the CT and then manual trim it from there.
Now, the problem with the CT as seen in AH2, at least how I perceive it, is that the CT has troubles when the speed of the plane is really high. Between 0~400mph it doesn't seem to be much off, but sometimes CT will fail to respond at very high speeds and I don't know why.
Clearly it is possible to trim the plane so the pitch doesn't rise, but CT won't just do it, and you have to do it manually.