I enjoyed the animated series, I really did. Ignoring the animation (which was what it was), many of the episodes were, in my opinion, condensed versions of live action episodes. Many of them really felt like they just trimmed the fat, but that's not always necessarily a good thing.
As mentioned above, "Yesteryear" is like, essential viewing. It's where I've taken my username "Thelin" from and everything. I loved the I-Chaya and, well, I just felt like it was the best the animated series had to offer. If you eventually decide not to watch any of TAS, watch this one.
I agree with Captain Robert April about "Magicks of Megas-Tu". I, the last time I watched through the DVDs, watched that episode twice. The first time it just seemed so dumb, but after the second viewing I had more appreciation for it. I think it's underrated, for sure.
My recommendation for TAS is just to take a few days, maybe a week, and watch the whole thing through. Some episodes are hit and miss, others really do feel like gems, but standalone they don't hold the same weight. If the animation is an issue, close your eyes and simply listen to the episode like it was on the radio. I think it's worth the time.