Recs.
Updated
Specs
Pros
Pro Semi consentual open world PvP
The game servers are divided into a blue zone (trammel), a red zone (felucca), and 3-4 more.
The red zone is set up so any player can attack you, or be attacked by you.
Meaning, any miner, or anyone hunting monsters is fair game to be killed and looted.
Pro Player crafting can make some of the best items in the game
Blacksmithing, leatherworking, tailoring, etc are available to be learned by your character.
With these you perform tasks for NPCs, and get runic hammers or sewing kits. These "may" imbue your armor or weapons with special effects. It's possible to make very strong equipment this way.
But also quite weak - vendors in the city are full with these randomly generated equipments for low prices.
Pro Player owned housing with a variety of customization
You can build your own house in this game (if you can find space available), either a small 7x7 house, up to 18x18 or even a castle. It's unlikely to find big vacant spots however as most available land is taken.
You could buy another player's house, and customize it to your liking - up to 3 stories high. Here you may then store your loot, crafting materials and loot.
Pro Freedom of class and skills (58 individual skills)
Want to be a sword wielding mage, carrying a shield, and play the flute? You can!
Want to be a master of animals, able to fish, dig up treasure, poison your enemies? You can!
The game allows you to distribute up to 700 skill points in a WIDE variety of 58 different skills, with up to 100 (up to 120 in a select few) per skill to choose from.
Pro Free servers maintained by players are available and fairly popular
If you don't feel like paying a fee per month, there's a number of free shards available. Ultima Online:Forever, among others. These kind of free servers generally have different or older rulesets and may have more pvp for those who seek it.
Cons
Con Very dated client
The game will feel choppy and sluggish - especially in popular areas if you're on a non local server.
It's 2D, but there's also a (less optimized and unloved by the players) 3D client which replaces the player and monster models with 3D versions. This is an issue as melee pvp combat generally relies on "who has the fastest computer or connection" in order to catch the other player.