This is an attempt to give a fair comparison / review of Everquest and Ultima Online.  Ultima Online has a history of Player Killing (PK) problems.  UO has addressed these issues and seems to be making good progress.  Note: at this time I've played Everquest for eight months but UO for only two days.

Cost
Both games cost essentially $10 per month.  Everquest is slightly cheaper if you purchase it three months at a time.  UO only costs $20 initially vs the $40+ that Everquest costs in the store.  UO gives you a REAL free month (no need to give a credit card number).  With UO you can set up an account and try it for one month without any financial obligation.

Customer Service
Both games have GMs staffed to provide management and help in the game.  UO has set staffing hours where they claim to have GMs on duty.  EQ is unpredicatable and often has no GM on duty.

EQ encourages veteran players to become "guides", these guides are relatively powerless but are intended to help players with questions about the game or problems (due to game bugs).  EQ has a very dictatorial attitude to prevent GMs and Guides from helping players "play" or "roleplay".  It is strictly forbidden for GMs and Guides to provide information to players.  This leads to leaked information and a lot of accusations of "favoritism".  EQ strongly gives the feeling that GMs only want to play with themselves and/or the very high level players.

UO has several levels of player involvement/staffing.  Companions (experienced players helping newbies); Counselors (roughly equivalent to EQ's guides) and Seers (experienced players that promote roleplaying).  There are three kinds of Seers - Seer, Elder and Ancient with varying powers.

Overall UO comes off with a lot more friendlier attitude toward players.

System Compatibility and Ease of Use
EQ runs full screen, preventing you from doing anything else while playing.  It also has a torturous and slow log in using MANY screens and log delays.  Once in the game EQ's user interface is fairly good (it does take a while to learn to fully utilize it).

UO can run either full screen or in a window and runs nicely alongside other applications (so you can surf the web, check e-mail or use an IM program while playing).  UO user interface is more difficult to use - items in a backpack are nearly microscopic little pictures.

Player Killing
EQ has a PvP switch that allows players to choose whether or not they can be killed by other players.  This is great except that it interferes with the ability to put on large scale roleplaying events.

UO has a reputation for terrible PKing problems.  They have designed a slick Karma / Fame system that marks players as Criminals or Murderers for stealing or killing other players.  This system seems to be working.  PKing in UO has dropped dramatically from what it used to be.

While PKing may be a problem in UO, EQ suffers a greater problem in that very high level monsters wander nearly everywhere and will kill low level players almost instantly. (only true "newbie" areas and towns can be safe for players in EQ)

Graphics
EQ is first person perspective (with other views available) 3D real time rendering.  This can make for a very immersive and natural feel to the game.

UO uses top down view and a somewhat clumsy movement method (either slow and lacking control keystrokes or pointing the mouse and right clicking to lead your character around).

EQ has fairly limited character customization.  UO has many more color choices.  EQ has many animated emotes; UO only has bow and salute.  Characters in EQ can only sit, stand or duck; characters in UO will actually sit on a chair if they move to the chair.

Player Objects (Housing, Ships and Pets)
EQ does not have housing, ships or pets.  EQ does not allow players to create unique objects.

UO allows players to purchase various housing styles all the way from a small house to a castle - real estate is very limited and thus acts as the primary limiting factor to prevent every player from having a house.  UO Players may purchase several different types of sailing ships to travel the seas.  UO players can tame animals to be their pets.  Horses can be purchased to ride or carry luggage.  NPC Mercenaries can be hired to protect player characters.  Players can custom craft unique objects in UO.  This is a huge advantage that UO has over EQ.

Grouping / Solo play
EQ virtually forces players to form groups (I consider this good).  But in EQ groups are limited to six players.  Also it is very difficult to maintain a regular group in EQ as players must be very close in levels (or the lower level characters gain no experience).

UO allows completely free grouping - very natural.

Communication
EQ has several types of ingame communication - group talk, normal conversation, direct tells to any other player online, guild talk and different languages.  EQ's communication is not as good as an instant message program but it works fairly effectively.  EQ's messages are in a chat box that also contains all other game messages.

UO has a more realistic communication system.  Players across the world can only communicate via ingame objects (communication crystals).  UO's messages appear above the head of the player speaking (and also in a "journal"). This can make this a less social game as it is more difficult to communicate between friends. Many players use an instant message program in addition to the game to improve communication with friends.

Travel
EQ makes travel very painful until high levels.  Druids are virtually essential for their "SoW" (Spirit of the Wolf) spell (gained at level 14 - which can take a normal adult six months to attain). Crossing the oceans in EQ is a painful experience (often waiting up to 20 minutes to catch the boat) with the boat taking 20 minutes to cross the ocean.  EQ has had a lot of "boat crashing" problems where the boats malfunction leaving players drowning in the ocean or not available for transport (GMs often fill in to transport players).  Travelling at night in some zones is nearly impossible for some races (humans).  Groups teleport spells become available to Druids and Wizards at level 29.

UO has teleport and gate spells that make it much easier for players to get together for an evening of playing rather than spending most of their available play time just getting together.  UO also has horses and player owned ships to aid in players travelling.

Character Races and Professions
EQ has many different races (Human, Wood Elves, Dwarven, Gnomes, Halflings, Half-Elves, High Elves, Dark Elves, Erudites, Trolls, and Ogres) and many classes (Wizard, Magician, Enchanter, Necromancer, Monk, Warrior, Cleric, Druid, Shaman, etc) (but not all class and race combinations are possible.  Your race and class determine your starting location which can make it nearly impossible to match up some combinations at low levels.

In UO all characters are humans and you are essentially what you do (wizard, thief, cleric, warrior, merchant - virtually ANY combination of skills you wish to focus on).

Economy
EQ has a completely broken economic system.

UO - I don't have enough experience to comment.

Combat
In EQ combat can be tedious and repetitive.

In UO I do not have enough experience to fairly comment on combat.

Magic
In EQ magic has many fantastic graphics.  Most EQ spells do not require any components.

In UO magic requires more spell components (reagents) than EQ.  Otherwise I don't have enough experience to comment.