I used YNAB since back when they used to just sell the software and maintained a subscription for a little while. I will say that their approach to budgeting has changed the entire way of how I look at money, and even though I have switched to GNU Cash, I have essentially replicated the envelope method there (it requires four entries per transaction instead of the standard two).
For anyone who wants to use this envelope method without paying for YNAB, I recommend checking out Buckets, which is another software that works similarly.