Most definitely worth the cost. We had previously done an Alaska cruise on HA and while it was OK, we were kind of underwhelmed.
When we did the Lindblad version a few years later (on the Sea Bird), we thought the entire experience was about as good as it could possibly be. Getting in to smaller places, like Elfin Cove, etc., made a big difference. We have taken a total of four Lindblad/NatGeo trips, with a fifth one coming up later this year. In my opinion, they are tops at what they do.