Obviously my experience probably doesn't reflect everyone's, so hopefully whatever stability issues others are experiencing can be resolved soon, but from my own perspective having it on-by-default would be pretty seamless at the moment.
The only things blocking it on by default now are:
* Implementing interactive key verification on mobile (happening right now)
* Cross-signing, so you don't have to keep verifying devices but can transitively trust them. This is designed and we demoed an initial implementation at FOSDEM in Feb; we're doing the final implementation now.
* E2E capable search. We have a PoC solution for this already, but want to rework it - work should start on this next week.
* Providing an E2E daemon so that non-E2E-capable clients aren't locked out when we turn it on by default. This is being done in combination with the search work and should start next week.
