For years, working in the register (of any account) in my 30-year old 72,000-transaction file has been sluggish. Saving any transaction for whatever reason always took a moment or two. I've often been tempted to give up on Quicken, but no other solution fits my particular needs.
Then, in the last few days, I was shocked to find edits instantly apply! I waited another day before confirming it appears to be sticking around. I can't find any recent release notes about this, but something somewhere was fixed and it's wonderful!