Disorganized thoughts: We've seen Alliance's blocky Peter-Jackson-style troll before with their first troll set. They actually paint up pretty nicely. Sets 2 and 4 here look a little too blocky; the Set 3 poses are a lot more dynamic and interesting.
Set 4 is possibly referencing the Orc Catapult set. I'm not really sure what's going on with the huge bases and limited number of figures and poses here. The Catapult itself looks like a lot of fun. Check out the one intrepid orc, apparently ready to take catapult-assisted flight!
The Fire Demons here are the long-promised "balrogs" (It's interesting to look at that post and see all that all the announced sets have now come to fruition. Good for Alliance!). The limited number of poses in interesting. They seem to be a bit larger than the trolls, but I'd also bet that the wings are separate pieces that take up space on the sprue. If the boxes are around $10-12, that puts the per-figure cost close to what Reaper charges for similar figures. True, they might be a bit bigger, but the sculpting also doesn't seem as good. I'd like to see them painted up before deciding for sure.
~Edit for 9/6/2017: I just realized that the box art here says that the Troll set 3 has only four figures total, while Troll set 4 and the two Fire Demon sets only have two figures each! Maybe that's a misprint, as it's a departure from the large troll sets Alliance has released already. But if it's right, then unless these will be much cheaper than Alliance's other sets, that makes the value proposition a little dicier. Even if they are as big as Reaper's larger trolls, let's say, if the boxes aren't cheaper than usual, the per-figure cost between Alliance and Reaper is about the same. And Reaper's figures are just better-looking.~
Still, it's great that Alliance remains committed to new fantasy releases. I'm looking forward to seeing what they come up with next!