In some ways "And another thing" is fresher with more of a story feel, and I liked that a lot, but I thought the humour was also cruder and less godlike and so I liked it less.
And finally, I'm not exactly sure how Eion Colfer had the balls to take on this project knowing full well that he'd be caught in the crossfire of the purists and all the infidel who remain blissfully ignorant of the significance of the number 42. Was it money? Probably. The fun of playing with gods? Well he certainly took that opportunity in both hands. Maybe we do need a computer the size of a planet to answer that question after all.
In the end though, the only real question worth asking is -- is this new instalment of the Hitchhikers guide worth reading, and, yes, I think it is, so don't be shy -- give it a burl -- even if it's only so you can complain about how Eion Colfer should have done everything differently, which is admittedly, rather fun.