So, first off, if you are talking about a class action suit in the US, you aren’t likely to win that. With something like 3D printing, there are a ton of variables that can change the printing time, the software makes it clear that’s an estimate, and you would have to prove beyond a reasonable doubt that they promised you a specific part would print in a specific time, every time. And I’m pretty sure you can’t prove they promised that.
Even in the best case scenario, you would have to prove they refused to let you return the machine (I have talked to multiple people who were able to return theirs), and then could only get damages for the difference between the purchase price, and the resale price, which would definitely not be worth going to court over.
That out of the way, yeah, a lot of the claims about the Form 3 as of launch, were at the very least severely misleading, I have certainly felt lied to at times. I honestly believe they botched the launch, released the machine too soon, and promised a lot they could not deliver at the time. However, I also feel they both have made, and continue to make, good faith efforts to meet the promised performance. It’s been a rough start, but I think you would fail to prove in court that they maliciously defrauded customers in bad faith, which is basically what you have to prove in the US to make false advertising stick.
If the printer doesn’t work for you, I would suggest you talk to Formlabs about the possibility of returning it and get on with your life, or sell it and eat the loss, because these things happen some times. I think you will just be throwing good money after bad, and wasting a lot of your time trying to sue.