So, after trying different coffee makers, different coffee, etc., we've come to the following conclusion. Our coffee doesn't necessarily suck. It is bitter from time to time so I may try the salt method to see if that does anything and we might ultimately switch to a different coffee. BUT, we've determined that our in-laws don't like our coffee because we make it differently for different purposes than them. We make it to mix into other stuff (milk, different syrups, etc). So we make it a lot stronger than they do.
For now, we're going to stick with the coffee maker we have, try the salt thing, and probably switch the general coffee brand we use.