yeah we're very interested in trying toploaders, we'll do a test rack next time we expand and switch to that if it goes well.
w.r.t. testing the main thing we did was try to buy a bit from each supplier a month or two ahead of time, so by the time we were doing the full build that rack was a known variable. We did find one drive lot which was super sketchy and just didn't include it in the bulk orders later. diversity in suppliers helps a lot with tail risk
"don't have to screw in every drive" is relative, but at least tool-less drive carriers are a thing now.
A lot of older toploaders from vendors like Dell are not tool-free. If you bought vendor drives and one fails, you RMA it and move on. However if you want to replace failed drives in the field, or want to go it alone from the start with refurbished drives... you'll be doing a lot of screwing. They're quite fragile and the plastic snaps easily. It's pretty tedious work.