My studio is across the hall from the Tape Project and I know the principals well. Good tapes for listening, the best ever, are available new, but they are expensive.
I had a Studer C37. It was getting too hard to find parts, and too expensive to service. Studer, and the new company servicing Studer analog recorders, no longer support the machine. Eventually, I had to sell it. The situation with the Telefunken M10 is probably similar. Studers from the '70s-'80s (A80, A820, B67, A810) are the best choice. Parts and service can still be found, and they are not rare. I would avoid Revox, and all other pro-sumer machines. They are not built to last, and have poor electronics. If you were in the US, I would add the Ampex ATR-102.
I had a Studer C37. It was getting too hard to find parts, and too expensive to service. Studer, and the new company servicing Studer analog recorders, no longer support the machine. Eventually, I had to sell it. The situation with the Telefunken M10 is probably similar. Studers from the '70s-'80s (A80, A820, B67, A810) are the best choice. Parts and service can still be found, and they are not rare. I would avoid Revox, and all other pro-sumer machines. They are not built to last, and have poor electronics. If you were in the US, I would add the Ampex ATR-102.