First, the content features a fairly linear questline that takes place outside of the wasteland in a Virtual Reality Simulation. Bethesda has really outdone itself as the graphics for Alaska were quite gorgeous and vastly different from the normal Washington D.C. color set that you might be used to. There are no missable achievements, if you go through the questline you will 100/100 complete it, as well as have access to some very nice rewards after you exit the VR Sim. The mission caters to those characters specialized in all weapon types (melee, rifle, sniper, shotgun) and even features a few new weapons (trench knife ftw!). The content takes roughly 4-6 hours to complete depending on the difficulty level.
I thoroughly enjoyed every minute of the mission pack and can't wait for next months DLC to hit, if you liked Fallout 3's previous offerings then this should be a no-brainer.