I'm recommending Towny over the claim plugin cause for starters monsters don't spawn inside of a town. Its easier to use with a clearer idea and you don't require items to use the commands. Towny works with the dynmap as well so its no real loss and on top of that you can spawn into other people's towns by typing /t spawn [town]. But it will still protect the areas that are claimed from outside use. You may need to adjust the towny settings if you were to use it cause it defaults with charging people to make towns and that should be a free feature in my opinion. You can also reward extra towny blocks to those who donate and vote so that way it will encourage donations and votes. Personally all in all I think towny would be more valuable of a plugin just cause overall it does the same thing but as I said it stops monsters from spawning in town.
Adding Towny just for that purpose makes no sense. First of all, Towny is a community plugin and doesn't fit players who play individually, which is one of the points we added the current claims system. The Grief Prevention claim system is for single / individual players AND also has a community side while Towny doesn't support individual players on its essence. The plugin name is Towny, it pretty much shows the intention of it.
Also, stopping mobs to spawn inside the claims is one option in the config of the current claims system. So, we obviously looked on that before and we chose to let mobs spawn inside claims because we look for challenging gameplay and not make it super easy. Mobs don't do damage inside claims anyway. If you don't want mobs to spawn in your claim, place torches, sea lanterns or redstone lamps.
To end, we are updating to 1.13 soon and we might accept suggestions for new plugins, so keep an eye on the forums.
