Plus user here. You have more tokens to burn through with Plus, and way less wonkiness (no more overloads, body stream errors etc). However, that being said, there's still massive issues with code processing at times, and I don't know if it's even getting any better tbh. For instance, just today I noticed it was messing up basic RegEx syntaxes (extremely basic stuff like escape characters), and then we got into a confrontation where it started saying that it doesn't have access to a regex validator, and that having one would take too much resources to run, lol.
All joking aside, OpenAI needs to start piping all of that code and calculation junk through a validator, and give us a code bin where to spin the code together with the AI while at it. Sadly, we are still working with very limited and sometimes broken functionality, and I don't necessarily see much progress having happened in the past two monhts. There are threads about it on a certain r-letter forum that has a separate sub-r-letter-forum for ChatGPT, where people have been noticing the same sort of lowered performance/increased error rate in code related topics.
(I had to rephrase this reply because I got timed out due to some odd "community filter" previously!)