For many years I suffered through QuickBooks because I just assumed that was the Only Way. The single biggest pain point (and it's hard to pick just one) is that QuickBooks makes it absolutely mind-numbingly difficult to bulk-change any entries in your ledger -- if you categorize 1000 items one way and your accountant later tells you to recategorize them, there is NO WAY (or at least there was no way when I did this in the early 2000s) to bulk recategorize items. So I remember the pain of having to manually change thousands of entries or, worse, doing indecipherable things like making single journal entries like "moving from X category to Y category".
Discovering ledger was a breath of fresh air because the source data is just text! If you need to change data or recategorize or make any tweaks whatsoever you have the entire world of text manipulation tools at hand. You can write shell scripts and use IDEs (and believe it or not Github Copilot works REALLY well).
It's just amazing to realize that the perfect accounting solution has been there the whole time and is vastly vastly SIMPLER than I ever imagined. I went through all the SaaS tools (Xero, etc.) and nothing felt right. Ledger just works and feels right.