Don’t be constrained by the tyranny of the “or”, but embrace the genius of the “and” (Built To Last by Collins and Porras)
Do both. Keep using free weight incline presses (barbell or dumbbells) along with machine inclines. IMO, don’t make every workout a “train to failure” routine. The incorporation of the balancing and stabilizing muscles of free weights is an important component of growth.
On failure days use the machines. On non-failure days use the free weights.
Or, you could do both on the same day, but I would not train to failure every workout, and thus, would not recommend that.