It's a great series, but a bit unsettling to read as it gets worse from book to book. By the time you get to Mostly Harmless it's like you're not even reading the same author as wrote HHGTTG. But I'm still looking forward to "The Salmon of Doubt", hopefully it'll be better than The Silmarillion in the cosmic battle of posthumous novels.
BTW, anyone here besides me with a HHGTTG nickname?