Here’s a good article (link below). I always had good luck with AKAI’s back in the day (I owned 2). However, the Pioneer models (and possibly TEAC/TASCAM) probably has the most parts, etc available at good prices. I will probably be looking for a unit myself in the next couple of years (I have tons of R2R’s recorded off LP’s, fm radio-concert specials, King Biscuit, etc from back when I was younger). I’ll probably go to a reputable dealer who carries used and look for one that has been serviced. One thing about semi pro models is wear and tear. If the model was actually used in a studio or band situation, the unit may have been used many hours on a daily basis in a not so optimal room (smoke, etc). Many small studios do not service or maintain their equipment like the big one’s did.
https://hometheaterhifi.com/editorial/purchase-open-reel-tape-deck-one/
https://hometheaterhifi.com/editorial/purchase-open-reel-tape-deck-one/