I've got the high rank for Spock's Beard at #4, so I guess I better explain myself!
Kansas was my introduction to prog in general. My favorite of the classic British prog bands is Genesis. Probably no surprise, then, that Spock's Beard would end up as my favorite of the 90s-era prog bands. There's a ton of those two influences all over Spock's Beard's fantastic and lengthy career.
A common theme I see in some of the other comments is that people enjoy the Neal era, but aren't as fond of the later stuff with Nick and Ted. My three favorite Spock's Beard albums are V, X, and Brief Nocturnes and Dreamless Sleep. One from each of the three lead vocalists, and I picked those three genuinely due to the strength of the material -- not just for the sake of picking one from each era. I'm even a pretty big fan of SB9, which is all over the place stylistically, but I find it to be one of the most enjoyable SB albums to listen to. With that said, yes, the Neal era is the most consistent. I confess to not really being a huge fan of the last two albums, or of the band's spiritual successor (PSA).
Rather than list off some favorites that any Spock's Beard fan loves, here are a few Spock's Beard songs I think are criminally underrated: Flow, Ghosts of Autumn, As Far as the Mind Can See, The Quiet House, I Know Your Secret
Spock's Beard is a band that was part of the soundtrack of my teenage and young adult years, and then continued making good music for a while beyond that. I connect with Spock's Beard on both a musical and emotional level. They're easily one of my personal favorites, and if they've about wrapped things up, that's a solid discography and a solid career.
And yet ... Neal Morse / NMB didn't make my list at all. I followed along with Neal for a few albums after he left SB, but by ? it all felt too same-y to me and I sort of found myself checking out. I jumped back in for TSOAD and TGA, because I was going on CTTE in 2017/2019 and both albums were being performed. They are fantastic pieces of work, to be sure, and I'm glad I got to see them live.
Also, the first Neal Morse solo album (the one with the blue cover) is underrated, and not just for the closing epic. Some great pop songs on that album.
Final note: interesting that the Spock's Beard high ranker (me) did not rank Neal Morse, and the Neal Morse high ranker (bosk) did not rank Spock's Beard.