Well, it was intended to be Part One of Two (or Three, at the beginning, but the plot-split needed didn't support "a proper middle film"), only quite late dropping any dangled promise of the sequel/conclusion by the title.
The cuts (one of which is the perrenial "Tom Bombadil problem"; or "...solution", depending upon the reader's attitude!) are notable but the retention of dialogue characterisation is perhaps superior to Jackson's treatment.
But ask any three Tolkein fans and might end up with four opinions on it!.
Visually, as a pure rotascope project, I think it's probably stylistically superior to CGI-enhanced modern movies (I saw a large swathe of a Transformers movie again, the other day, definitely a case of"just because you can, doesn't mean you should"...), but a different time and doubtless they'd use "artification" algorithms these days, when any fool can redraw themselves as a cartoon dog in realtime.
My opinion, I don't think it spoils the books (or, because it is only partial, spoilering them). Maybe a niche 'historic' treatment for post-Jackson audiences (and non-readers, in particular), but for me (probaby didn't see it in the late '70s, but would have by the mid '80s, at a similar time to Tron from '82) it works well.
Yes, the Jackson trilogies are a visual tour-de-force (plot-rewriting aspects aside, and the resulting "green tide of ghosts" that... well, I admit I enjoyed the friendy rivalry of "that only counts as one!", at least, as I did the shield-surfing and barrel-hopping elsewhere, even if off-canon). But if you're determined to read (or reaquaint yourself with) the novels then Bakshi's work will definitely interfere less with that process. IMO, naturally.
(Caveat: I haven't seen the Bakshi for maybe 20 years. I think I last substantially read either Hobbit or LOTR perhaps around ten years ago. I've seen the Jackson sets (idly, in passing) at various times more recent than that, as well as upon release. So I may be differently rose-tinted, or otherwise. Not yet seen the Netflix/whoever ME-based mini-series at all.)