I've purchased many of their forest sets (includes 4 forest bases). They offer each base individually or as a set. You can also just buy the bases or (as I did) buy the set with the bases and the ready made Woodland Scenics trees. You can see my completed forests below. I have 4 complete sets of the woods completed with another two that just arrived days ago that I'll do up.
Having uses several different kinds of stone walls over the years I must say I really like the "interlocking" system used by the AoW (Architects of War) stone wall and overgrown stone wall sets. This allows you to do corners or straight sections without the corners looking odd (like you just put to straight sections together). You can see their stone wall set below. I have 4 setes of the stones walls in my collection.
I highly recommend picking up the overgrown stone walls set as they allow you to easily transition between the hedgerow sets (covered below) and stone wall sets. I have 2 of the overgrown stone wall sets done as you can see below.
I love the hedgerow sets they offer. I have 4 of the hedge row sets --- one complete set is pictured below. They include all the tress and clump foilage that you'll need to properly complete the modeling.
Last (but not least) is the many other sets they offer. I have completed their turnip field and pig sty (complete with pigs, but not pictured as I still need to paint them) as seen below.
I have two of their dark age buildings that I'll use for SAGA gaming and their garden and tobacco field as the big sets still needing to be completed. I've also got their road signs, mine field markers and campfire sets on top of all that ... spectacular stuff that really has the little details that make all the difference when they are on the tabletop.