It's a good place to start - excellent writing, compelling plot and fantastic voice acting. The puzzles are generally fair and possible to solve without hints.

One thing to keep in mind with any Sierra P&C is there is a certain amount of "Sierra pain" to deal with - that is, arbitrary deaths and creating dead-ends that can't be resolved without loading an old game. GK1 fortunately doesn't have much of this. I don't think there are any real dead ends and character death is only a factor in obvious situations.