Hi and welcome to R2R
If you want better sound quality then R2Rs will generally sound better than Cassette but there are some very good cassette decke out there that will give the best of the R2Rs a run for there money, personally I prefer the 2 track machines as they have a greater dynamic range and no bleed through from narrow tracks.
There are no relaiable R2Rs these days as they are all getting very old, so dodgy old capacitors are the biggest cause of failure.
Some of the last machines made were the Tascam BR20 and i can thoughly recommend them as very good performer and as reliable as you can get nowerdays, I have 6 of these machines, the Tascam ATR professional machines are also excellent but quite rare in the UK now. Tascam was the professional version of TEAC who also made some very good machines for the domestic market the latter ones of those were the X1000 & X2000, I have a Teac 3440 and an X1000 and they are both good machines.
Revox made some wonderful machines and the latter versions were the semi pro PR99 Mk1, 2 & 3 and they are the ones I would look for if you want a revox, but if you chose revox be prepared to have to completely recap them as the frako caps in particular have a habbit of failing short circuit I have a Pr99 mk1 & 2 but both need work on recapping.
Studer were the Professional range of the Revox machines and these are superb performers if in good condition and also share the same capacitor problem, I have a Studer A810 which is my pride and joy
Otari made some very nice R2Rs and in europe the MX55 was an excellent performer and very good build quilaity, I have 2 of these machines and have never had to replace a cap yet, in USA the MX5050 versions are very highly regarded
Akai made some fine sounding machines and the top of the range GX646 & 747 are very nice but expensive, Some Akai machines also have a problem with failing transisters which are now obselete although allternatives are available.
Sony also made some great machines but I have never owned one so cant offer an opinion on reliability?
Tandberg made some superb machines 30 years ago but good ones are quite rare now, Ali Tate has a very nice example
7.5" is very good and makes the best use of the tape 90mins on a 10.5", 15" sounds tighter and cleaner but eats tape up the same tape in 45mins
Oh and then you have to find some decent tape that will not have sticky shed
The maxell UD & XL range are very good and still available are the Pyral LPR35, SM900 & 911 and ATR tapes but at a cost
Hope this helps
Last edited by 337alant; 22-09-2016 at 20:54.
Turntable - Garrard 401/Jelco 750L/Ortofon Kontrapunkt B, Pioneer PLC 590, Micro Sieki MA505 , Denon DL103R - DIY Paradise Phono stage - Reel 2 Reel Studer A810, Otari MX55,Tascam BR20, Revox A77, B77, PR99, TEAC X1000 & 3440, Digital HTPC / Young Dac - Preamp - DIY B4, 821, Power Amp's DIY Avondale NCC300 Mono Block, Speakers Wilmslow Kit Volt BM220.8 / Scanspeak D2905/9500