I don't think History of Western Philosophy is bad but it is opinionated. If someone were expecting either a dispassionate overview or heartfelt enthusiasm for all philosophers past I can see how they'd come away disappointed. Especially when he's particularly dismissive.
If you go in expecting Russell's view of Western philosophy through the ages then you'll get just that.
I thought Russell's History of Western Philosophy was interesting precisely because it gave Russell's personal view on all the philosophers. (This is just like Kenneth Clark's Civilisation.) There are already dozens of dry textbooks out there, whereas Russell was uniquely positioned to write an entertaining opinion piece on the topic.
Read it main years ago and found it both enlightening and a good read. There were parts whre he was clearly struggling to understand the work of particular philosophers, but he had no secret of the fact in the book. It was interesting to a great mind grappling to understand the work of another. Parts made me chuckle, too.
Since he’s up-front that he’s gonna be including opinion, and about his own limitations when it comes to presenting certain philosophies (IIRC for Bergson he was like “look I can’t figure out a way to explain this that doesn’t seem like total bullshit, but I’ll try”) I don’t really get the complaints about the book. I think it’s great. Why would you want Bertrand Russell to write such a book and not provide his analyses? It’s better that way! There are plenty of similar works by people mainly known for writing their histories of philosophy. Go for those if you want a just-the-facts version.
Agreed. I'm much more comfortable with "this is my take on this subject, and here's how I'm a bit biased, but I'll try anyway to be as objective as I can as well" than "this is the way things are"-style proclamations.
If you go in expecting Russell's view of Western philosophy through the ages then you'll get just that.