Really more of a 3.5, better than average but still a tad simple and uninspiring. Generally a good story, but I liked it better when I was a teenager. The 3rd book in the series wasn't out then, so when the trilogy was on sale as a single kindle book, I snagged it for nostalgia's sake. It didn't keep me thrilled or on the edge of my seat, nor did it blow my mind with new sci-fi far-outness, but the characters are likable enough, the world is just fun enough to host the adventure, and the action:introspection ratio was balanced, if predictable.
The whole premise of the accidental arrival of advanced humans among the less developed natives is cool, a lot can be done with the trope, and this trilogy does a bit with cultural impact, prime directive type stuff. The alien flora/fauna is diverse and mostly reasonable in the context of the ice world, and whatever seemed "unlikely" was still not too far-fetched to enjoy and fit the plot. The characters were stable, reliable, but really didn't evolve much and were perhaps a bit ... not stereotypical exactly, but not of great depth or surprise.
Respect to Alan Dean Foster. I'll probably always consider him a favorite though I've read only 15 or so of his many books, and most of us have seen and enjoyed many of his book/movie tie-ins, so you know, what's not to love? But I think I need more intense/enveloping books nowadays, to really grab my interest, like Iain M Banks Peter Hamilton Dan Simmons Gene Wolfe Neal Stephenson China Miéville...
I still have Alan Dean Foster's _The Damned Trilogy_ that I downloaded during the same kindle sale, so I'll give that a shot, but I think I won't be reading much more of the classic 70's like this, Heinlein Niven Adams.., Maybe I will though. After all, I was off classic rock for a while too, but then went back to that!