I have no problem answering these questions.
For your first question no I have not seen any long or short term issues with housing my snakes in a rack system.
For your second question, That is a personal opinion on how you house your snakes. Most of my snakes were hatched then raised in rack systems so they have been used to them for their whole lives. It really depends on how many snakes you are wanting to keep and if you plan on breeding or not. One reason I would suggest a rack system over cages tho would be that it is much easier to keep up the humidity and regulate the temperature. Most racks have enough air holes to have constant circulation but not enough to have low humidity.
As for your third question, Almost all of my snakes have no hides. The only time one of my snakes have a hide is if they are skittish or not eating on a regular basis because they are stressed out. You are correct that with racks the back of the tubs are particularly dark giving the snake a nice comfort feel and makes them feel secure.
I hope I answered your questions with enough detail but if not just let me know and I will try my best to answer them better.
Thanks everyone fore the comments! I worked very hard on this room getting it just how I wanted it to be.
I will defiantly be updating with new videos more frequently now that a lot of people are asking.
Thanks!