To save you the read, they will send you aligners that don't fit. They will either be warped and twisted like they melted a little, or your molars will fit snug in the tray, but your front teeth aren't in, and when you push on your front teeth to make them snug in the tray, your molars will pop out. Like a see-saw. This WILL happen. It WILL take weeks for you to be able to resume your treatment. I had a four-month plan, it took six months to get this far, and I haven't even started month four yet.
If you want to hear more:
I had to go in for a mid-course correction at the end of month two. The scanned my teeth with a laser, and month three (when they arrived) they fit really well! Awesome, right? Not exactly.
When it came to putting on in month four, they didn't fit. The top row was the see-saw from the above paragraph, and the bottom row magically assumed my bottom teeth were already straight, when they knew they weren't. They said it was a manufacturing defect, and I waited yet again, and the new ones were EXACTLY the same.
I went back in for another laser scan (surprise, right?). This time, they realized that the plan they made was flawed and destined for failure. Although month three fit, so I was completely on track, month four was jacked up, and it was impossible for my bottom teeth to fit side by side.
So they sent me a brand new plan. This time, eight months. This new plan also leaves me with a gap in my front teeth because to correct for their screw up, they needed to push all of my teeth forward. Also, they wouldn't admit fault; they were trying to use the dentist who made this plan (whom I also have never met) as a scapegoat by constantly telling me they don't know anything, they aren't a dentist, etc.
This is a textbook example of a company that grew too big too fast and was unable to identify their growth plans and process gaps in order to deal with issues like this. They also, in my case, would go nine days without responding to be, and it takes time to make new aligners. Keep that in mind that you never really know if they fit like they're supposed to. In my case, that final aligner's gumline was a good 3mm above my actual gum line, and of course, this was because the teeth were crowded and not straight. It's like trying to shove 100 singles into your wallet and fold it in half. You can't. Too much bulk.
So remember me, friends, on your journey to straightening that smile. unfortunately, SmileDirectClub will not let you see each week's trays ahead of time to so can try to protect yourself from this nonsense. You're going to have to take a leap of faith, and I truly hope you don't get burned.
Bottom Line: No, I would not recommend this to a friend