I have a subscription to ultimate. Its terms seem quite fair to me - you're effectively buying a specific version (the one you get to keep) and paying for it in instalments over the year. Until your new subscription starts you have not paid for those interim releases. They send conspicuous renewal email notices well ahead of making renewal charges which is more than most recurring subscriptions of all types provide.

So personally I'm willing to extend some trust to IntelliJ.

As a product it's quite pleasant to use. For Java development it strangely lacks quite a few of the nicer features of Eclipse, but its good quality support for so many different languages (e.g. for Rust) compensates for that.