Owl's Well That Ends Well and Just For Sidekicks are the only Spike episodes that I don't like all other Spike episodes are good in my opinion except for Inspiration Manifestation of course that episode is better than good, it's great.
Every episode is good in its own, unique, individual ways. So yes, they are good in their own, unique, individual ways.
I was kinda bummed last season when the Equestria Games were TOTALLY glossed over in favor of being a Spike episode. Not that I have anything against the little guy but that's probably my biggest complaint about him.
It's up and down for me. He'll have a great episode which is followed by one that has him acting like a complete fool. Still love that little lizard though.
Spike is an decent character in the show, he does mess up sometimes and all that but I still like him.
I'd like to see Spike grow up a little on the show. It's been over a year in-universe, maybe a year and a half. I think he and the CMC need to show some outward sign of growing up. For the CMC, it would obviously be cutie marks. For Spike... I dunno. Maybe wings?
Dim Sum turned out to be a stolen ZeviantArt OC called Krystal the Dragon. However, Spike did spend some time with a dragon girl named Mina in one of the comics.