Less bugs, more straitjacket
Serpent Isle is a large, well-plotted sequel that removes most of the infuriating bugs from Ultima VII: The Black Gate. The world of the isle is richly textured, with extensive dialogue and a series of quests to navigate. More so than The Black Gate, Serpent Isle is the natural culmination of the Ultima series style.
For all the density and complex interaction, Serpent Isle is a far more linear game than its predecessor. Though the game world is larger, you are shown small chunks of it at a time, with specific quests to complete before any further progress is possible. In structuring the game this way, Origin have removed the most attractive element of The Black Gate - unlimited freedom. A large world seems a bit wasted if you're only going on a guided package tour of it: for most of Serpent Isle the player is kept firmly "on quest".
In terms of game mechanics, Serpent Isle trades annoying bugs for verbal diarrhoea. Yes, atmospheric dialogue is great, but some of the game characters appear to have three-act plays in their heads. And a fair amount of the game depends on trade of information, so there's no real way to skip it.
The Bottom Line
Those who like to be marched through a game may prefer Serpent Isle to its maligned predecessor, The Black Gate. The storyline is particularly strong, with classic elements of betrayal, murder, and redemption. For me, however, the game felt too much like a path with high walls; the opportunity to go sideways sometimes would have been appreciated.