Neverwinter Nights 2: NWN 2: MotB Review at IGN

IGN has assigned Mask of the Betrayer a "great" rating of 8.5/10.00. Editors had this to say:

Meter issues aside, you'll find Mask of the Betrayer's narrative to be well done overall. You don't spend loads of time dungeon crawling mostly because there aren't that many huge dungeons to crawl around in. Most combat areas are smaller and feature less enemies than you might expect with a game like this, keeping the focus on plot and character development. A notable exception is the Academy, which requires a surprising amount of problem solving skills to complete. It can be an enjoyable diversion, featuring a number of side-quests to absorb your time like a golem boxing match. It really jumps out of nowhere, however, and slows down the game's otherwise high-tempo progression. It isn't really a problem, just unexpected. When you do head out into the field to fight, expect some challenging resistance, as many foes in the game will easily shred an improperly buffed party.

And in to sum it all up:

Mask of the Betrayer is a fine expansion pack from Obsidian. It's a more stable experience, seems to run slightly better, and more importantly delivers a narrative that, for the most part, proceeds along without getting tangled by the catches of cliche. Its characters and their interactions are sure to strike many satisfying chords within the hearts of the Dungeons & Dragons fans, though those uninitiated in the ways of these types of games should steer their attention toward the original before tackling this high-level affair.