With as much discussion as has taken place over whether to keep or replace the Cub yet still unable to reach a decision, I would guess that you'll be second guessing whatever decision you make for years to come. You are suffering from what is known as 'analysis paralysis' i.e., afraid of making a mistake. If I had to guess your occupation, it would be engineer for the reason that I've seen so many engineers freeze up when making even the simplest decision when their own money was involved. (FWIW, I'm an engineer.)
You've been given reasons why you should keep the Cub. I've seen few if any reasons given as to why you should spend triple the money on a modern-day tractor with its modern day engine and systems. The Cub was built in a time when successive years showed improvements over the prior year's model. Sometime between then and now, that corporate business model was replaced with decades of cost cutting. If the Simplicity has not been a victim of this, by all means buy it.
You've heard the saying, "You can lead a horse to water but you can't make him drink." In this case, the horse is standing at the water's edge: Please take a drink, or just flip a coin.
You're right...absolutely. Actually, I'm a retired elementary teacher...but interesting to hear about the engineer decision-freeze you refer to. No way to know if the Simplicity designs have fell victim to the cost cutting or not...can't imagine why they wouldn't have. Thanks for your thoughts. I know I need to make this decision soon.