I've explained this on Slashdot before: Even if such plants reach "break even", creating more available energy than they use to run, they can't possibly scale to production use because the tests that are even _slightly_ successful use tritium as a critical fuel component. And the only viable source of tritium is ordinary nuclear fission reactors: there is no scalable natural source for it.
There is _no_ fusion technology ever tested, nor realistically proposed that does not rely on tritium. And every source of tritium itself, either earth-bound fission or potentially solar sail collectors for solar tritium, is _itself_ far more efficiently used as a straight power supply by itself. Sustainable fusion is interesting as a technological accomplishment, but it's not a viable power source unless the need for tritum is eliminated.
Several of the designs have additional tritium as a byproduct of the process, thereby being self sustaining.