The Otari MTRs sound great, even with stock electronics - excellent transport as well. I have a 1/4 inch MTR12 and it’s a great deck.
If you really decide to get into R2R and "master tapes", I would advise that you buy TWO machines, the appropriate monitoring equipment and calibration tapes.
Every studio produced tape would have had line up tones at the head. To get the very best out of each tape, you have to learn how to adjust the playback (repro) to give you the correct level and a flat freq response. Learning how to calibrate both the repro and record side is crucial to getting the best out of a fabulous medium.
I have 5 R2Rs - a half inch Studer A820 and 4 x 1/4 inch machines - Otari MTR12, 2 x Sony APR 5000 series and a Studer A807/II.
I also have about 100 x 15 IPS 1/4 inch production masters (incl Beatles, Floyd, Doors, Peter Gabriel, Miles Davis, Nina Simone etc). I would not dream of playing these regularly through my machines - they are far too valuable and irreplaceable.
Hence, upon purchase I copy each master onto a) new RTM 1/4 inch tape stock at 15 IPS with Dolby SR and b) onto 192/24 high res with a Prism Sound A2D interface. I can then play the duplicated tape as much as I like. The original gets safely stored. It takes me an evening to do a single tape.
Without a shadow of a doubt, high speed R2R from a high quality recording is stunning. You need deep pockets and the willingness to learn. It’s a lot more hassle and far more expensive than digital.
Recording studios went to digital, as it’s far cheaper to make the music in the long run. A 2 inch 762m tape for recording the multitrack session (approx 16 mins at 30 IPS) costs about £350 or USD 500. 1/2 inch tape for the 30 IPS stereo mix down is about £180 or USD 250. That’s a cost, which up and coming artists can’t afford to pay.