A decent show that, yes, wasn't the best, but certainly not the worst. It had it's moments and was a pretty good watch overall.
Season 1 was probably the best because it had really stuck to the novel in the first six episodes, but then started to become more of the Indiana Jones type era which was still good but not as good as the first six episodes.
Season 2 was second best as it concentrated very well on the adventure style themes and did it pretty well. Season 3 was probably the worst. It tried to tie everything together and just came up with this extremely weird plot and difficult to understand storylines. But still, worth a watch if you want to get a mild thrill.