Two years of a 4 day work week and I still argue with myself about it

I moved to a compressed schedule at my accounting firm in Columbus about 24 months ago. Tuesday through Friday I work 10 hour days and every Monday I'm off. My productivity numbers stayed the same and my boss loves it, but my weekends feel like they got shorter because I spend Sunday dreading that Tuesday through Friday grind. Some coworkers say the long days burn them out by Thursday, while others swear they'd never go back to five days. I guess my real question is, does the extra recovery day actually count as rest when your work days are so heavy? Has anyone else tried both setups and kept a clear winner in mind?