I've had some experience with overhead sectional panel doors, probably nothing compared to yours. I have never worked on the roll up doors except for the electrical. My only memorable experience with roll up steel doors was in a mine years ago, stopped to wait for the door to go up all the way, door went to the top, the chain broke and the door came down like a guillotine.
Seems to me the roll up doors don't "balance" like the overhead panel doors do. They seem to require much bigger power openers and the handchain needs more effort to move the door more slowly. Why would you recommend them, and what are the problems with panel doors that you experienced?
Those are very good points norite, and I'll be glad give you some info about the two types of doors, sectional and roll up. Again, I strongly recommend getting a quality door of either type, you'll get far better service in the long haul than trying to save a few bucks up front. And there's a reason I said avoid "Overhead Door" brand doors, not that I'm trying to slam the company or that I have a personal bent against them, it's just just over the last 30 years they have been the innovators of making it "cheaper", all other companies have had to change their product to compete with Overhead at the bidding level. Which is directly related to why I recommend avoiding sectional doors of large size, all door brands now have a "cheaper" product in that line, and a door that's 14 x 16, 16 x 16, 16 x 18, that's a big door, cheap just won't last. I've been away from the door business for some years and don't know the latest about the different brand doors, but Raynor used to make the best quality sectional door out there.
As for comparing sectional to roll up, it's actually simple, the roll up uses less parts, no hinges, no track rollers, no cables to break, bottom line. And they are very compact in the space they take up in a shop, simply a covered roll mounted on the wall above the door header, no tracks going back into your shop ceiling requiring hangers from the ceiling like sectional doors need. I worked on a 20 x 20 once in a coal mine shop that someone had bent one of the top track on one side with something, then the door was raised and the bent track pulled the rollers out of the three top sections making them hang down on one side, that was an interesting mess to repair. Also the guides on the wall are far different with the two doors. The sectional will use a roll formed thin 2" track, very easily bent. A good quality roll up will have 3/16" thick 3" structural angle guides, very much more durable than a sectional door track. If either door is installed properly, they will give years of trouble free service. But from a installer and repairmans perspective, the roll up is more trouble free simply from its design and from using less parts.
Now, the door you saw crashing down, very simple; the chain broke because the counterbalance spring inside the roll shaft was broken. The electric operator and chain was simply hoisting the door up all the time, which it's not designed to do. Eventually the chain gave up, hence, door came crashing down. A broken spring can and does happen on both type of doors and can have the same result. The difference is, on a sectional door the springs are visible and someone generally notices it's broken where on a roll up they are inside the tube shaft and not visible. That's the reason roll up door makers typically use high life cycle springs making them last longer. A broken spring on a quality roll up door is actually quite rare, but it does happen. But to answer your question, the roll up door counterbalances just as well as the sectional door when either are installed properly.
Which brings me to my next point, the electric operator. I've worked on so many doors that someone doesn't have the springs adjusted properly and they use the operator to hoist the door up and down. They are not designed to do that. This includes the door at you home garage. The operator is designed to "move" the door, not "lift" it. Springs on sectional doors progressivly weaken over time because they use small gauge wire. One should once a year lubricate the rollers and springs on their garage door with motor oil, then disconnect the operator arm from the top section and see how the door works by hand. If it's heavy to lift, you need to get a door service man to adjust the springs. Rolling steel doors don't suffer as much from springs getting weaker because they use a large gauge wire size for the coil, but they too should have an occasional "look over" by a door professional to insure proper service. If someone would have done that, you probably wouldn't have witnessed that door crashing down.
Here's a thread that has two pics of roll up doors we installed back in the late 70's, both are still in use today.
https://www.heavyequipmentforums.com/showthread.php?t=15918