A ball injector vape is everything it's cracked up to be and this one has a great setup/price. I have a Hot Rod which is the previous offering from Old Head and it's lower-powered compared to the Freight Train but solidly built. I also have a B-Zero which compares with this price-wise and I assume in terms of power: even a lower-priced ball vape setup such as these are amazingly powerful and probably surpass the two you mentioned in terms of future-proofing, build robustness, and power. The other two would be more portable, obviously, though the Minivap is not very mini at all and is really quite powerful as well.
Edit: the only notable qualification I've seen with the Freight Train is that the hit is more constricted than the Cannabis Hardware heads. My understanding is that the FT's resistance was tuned to feel like a combustion bong toke.
Edit 2: If you are shopping for lower-priced ball injectors I would add one caveat: in my experience the e-elev8r is probably the lowest-performing ball vape because of its constriction, limited size and capacity for mass, and because it's a challenge to get enough of the coil to contact enough of the heater (not super-challenging, however). That said, I have one I use all the time for closer-heated flavor bowls and it's a delight for that purpose. Just wanted to point out that while the e- or dc-elev8r will fully roast a bowl with excellent flavor, it is surpassed by the others you'll see in terms of sheer power.