I know it is a bit late, but I came across this and just in case it helps anyone else here is what I know.
Full disclosure, I work for Magnext which sells tape drive libraries and sells their own brand MagStor which I put together and make software for. I will try to be honest though : )
Off the top of my head...
If you use tape for backups, do you use LTO? If you use LTO, do you use LTFS or a different standard/format?
LTO is the only option. You could use other things, but you would find support in the future difficult.
What kind of tape drive/library set up do you have?
The setup you need depends on your requirements. If you only have a couple 100 TB of data and you can access it all from one computer, you could get a single SAS drive and have someone manually load and move files to the tapes. This would only require a few tapes and the transfer would take about a day per tape. May I recommend our MagStor SAS drive (shameless plug)
If you need to be able to easily push and pull data from multiple tapes from many different computers, at this point you would need a library connected to your network. Setting this sort of thing up can be difficult without someone experienced in IT or assistance from the people you are buying the hardware from. The most important thing here is that you have a libary that works well. Most of the parts that make up the libraries are actually the same and the only difference is the firmware installed on them. If that was not the case, it would be prohibitively difficult for us to repair them. This also means that there is not much difference between which one you get, but I could ask our technicians which they prefer if you want an expert opinion on that.
What software do you use to manage your hardware?
LTFS Software recommendations
PC: PreRoll Post and XenData6 work station
I don't have as much experience with the software side of things, but I hope that helps some.
LTO is the standard when it comes to tape, but as it stands right now the newest version of the tapes, LTO-8 cannot be sold because of a legal battle between Sony and Fuji Film. Once they can be sold again which will hopefully be very soon, LTO-8 is a good choice because it is 12TB for ~$150. (kind of guessing since they cannot be sold right now)
All LTO drives can read up to two generations back and read one generation back. The only drive that breaks this standard is LTO-8 drives which can only read and write one generation back due to a physical change in the tapes.
I myself have not had much experience using LTFS on a PC as apposed to mac, but there is plenty of different software out there to get you up and running on whatever platform you choose, though you will likely have to pay a monthly fee.
I am sure I have missed a lot so If you have any more questions, feel free to ask and I will do my best to answer. Tape is complicated, but it is also the most economical and longest lasting option. Good luck!