Pros:
The graphics and sound are terrific.
There are several dozen dungeons to group in.
Each dungeons is an "instance"; that is, your group is the only group in that dungeon.
No respawns. Once you kill something it's gone, so if you need to get out in a hurry, your way back to the zone will be empty.
It's impossible to lose your corpse. Corpses "pop" outside the dungeon entrance after adventure is over (if you don't get a rez of course)
Experience is currently good, but will likely get lowered (nerfed)
Cons:
Figuring out how to "get started" with LDoN is somewhat complicated. Fortunately, enough people know how to so all you have to do is ask
To start an adventure you MUST have at least 4 players and the number of levels between the highest and lowest must be 7 levels (some argue it's 8). More often than not, more than 4 players is required and it can take a very long time to get a group together. This is the biggest downfall of the game and why I became tired of the expansion so quickly.
Currently, most groups look for the same class of players, so some classes tend to take much longer to find groups (if at all). For example, warriors and enchanters generally have no trouble, while druids are usually picked just to fill the 6th spot.
New items are purchasable only with Adventure Points, which are gained through successful adventure completions. Even the higher-priced items don't seem that great for most classes.
You tend to find alot more bad attitudes in LDoN as adventures tend to go very well or very badly. When they go badly, I've encountered many people who tend to get personal and insulting.
Although there are different "themes" for the dungeons, the overall quest is the same: kill, loot, kill, loot,...
The quests have a maximum time of 90 mins plus an additional 30 to complete a failed mission. In addition to the time finding a group, running to dungeon entrance, and splitting loot, the amount of time required can be several hours for one adventure.
With that being said, this is a great expansion. Find or create a group of up to 6 people and ask for an adventure. You will get a dungeon created just for your group. You'll have 90 minutes to complete the adventure.
This is great because you know what your time commitment is. If you're a casual player you know you aren't expected to be there in the group for the next 6-8 hours to help everyone. And the time goes fast since the action really doesn't stop while you are in the dungeon, at least it doesn't stop if you want to finish in time.
The dungeons are well designed, and you would be surprised what the designers have been able to do with a graphics engine as old as EQ's. It's all very immersive!
I would strongly recommend this expansion to anyone. It puts a different kind of fun into the game.
I gave this expansion 5 stars for the improvement and ingenuity it has brought to the Everquest world.