LiS will be even more popular with grid utilities. Super high specific energy, but low overall discharge weight + low cost of Sulfur means a popular, stationary battery perfect for grid tie in. Ironically, it's even less dense than li-ion.

The current issue is commercialization (i.e, doesn't exist) and low conductivity of the sulfur cathode (meaning a low discharge rate to avoid self heating) -- it could be a decade + away.