Optane SSDs have left a good impression here at TR. Some folks sneer at the performance claims Intel makes for them, and it's true that the sequential operation figures aren't shocking. The Optane drives are unmatched in terms of responsiveness, though—much the same way early SSDs weren't a lot faster than HDDs in sequential terms, yet blew them away in random performance. The fastest solid-state drive on the planet right now is Intel's Optane SSD DC P4800X, and the boys in blue just announced that you'll soon be able to buy a double-capacity version storing 750 GB.
The SSD DC P4800X normally comes in what is sometimes called an HHHL form factor, referring to a half-height half-length PCI Express card. However, the existing 375 GB size isn't a lot of capacity for the physical space required, so doubling the storage should make sticking a few P4800Xes in your servers a less-painful proposition. If you're really strapped for space, Intel is also about to start offering the P4800X in a 2.5" form factor with a U.2 connection. U.2 is basically "M.2 with a cable," so the performance of these drives should be identical.
Intel didn't say how much the double-stuffed Optane SSD or the U.2 variants would be when they hit the market soon. The existing 375GB SSD DC P4800X goes for $1730 on Amazon, so the new drives will probably be well into "if you have to ask" territory.