I own four Teac units, the A2300SD which is two channel Dolby and which I use to transfer two channel masters to 4 channel sound via a Fisher CAV-875 audio processor, along with a 3340, a 3440 and a 2340R. I own three Akai units, a 1730-SS, a 1730D-SS and a 1800D-SS. All of my Teac machines have been worked over and renovated by the fine folks at Audio Alternatives. I am very satisfied with all my reel to reel units. I also own three Akai CR80D-SS 8 track record/playback units and a Dokorder MC70A playback only unit. All these 8-track units are 4 channel. And finally, I own a Lafayette RK-890A 8-track stereo tape unit.
I would venture an opinion that any Teac unit is worth investing in, again, if the price is right. My Akai units all have been redone, again by the fine folks at Audio Alternatives.
Good luck in your search. Once you get a good reel to reel unit, you also will be hooked.
MTGC (Michael)