About taxes: if you book a *A award flight with LH then prepare to pay an enormous amount of taxes. UA is generally better. I'm also a LH*G and I usually have to pay up to 5000NOK for a C award (plus points, of course). These extra costs will stay through *A awards

Furthermore, generally what ScandiGB says. Just make sure they do a bit of work for you and look further than just their login screen.

There are a few award availability tools available that collect data from multiple sources. You'll find some in the 'Travel Tools' forum.