Here were my general experiences - I saw on here the confirmation that it was open while having an early dinner at Disney Springs. We decided to skip shopping and The Void and instead took a Lyft over to HS, arriving at 6pm. Went right back to TSL and it was pretty crowded, but you could walk through it. We got in in the long extended queue for SDD and the CM said it would be 3 hours. It took us about 25 minute to make it to the "real" queue, and 80 minutes total. That 80 minutes went pretty fast - there was a constant light drizzle so it was never super hot, the line moved constantly and there was a lot to see. Plus just the general air of happiness and excitement in the queue.
While we did SDD my daughter did TSMM, which she said was a walk-on. We forgoed aliens because it was posted at 80 and we weren't too excited to ride it. Instead we walked around taking pictures, did a photopass at the buzz statue and then did TSMM (posted at 45 but practically a walk-on). We left for a while to get drinks & ride ST then came back to take pictures in the dark.
OK, so I'm kind of a whimp. I only started doing BTM a couple of years ago and now I love it, and I'll do 7 Dwarfs and love it, but won't touch Space, Splash, Everest or RNRRC. SDD was pretty scary for me because it was so high and exposed (just those thin rails, compared to the solidness that is BTM & 7DMT). However, it was also fabulously fun. I would probably do it again. I didn't get that dropping feeling in my stomach, which is a hard line for me. I do get vertigo, but that's more likely to happen on Star Tours than SDD. Hope that helps.