All things considered, 1990 is probably my favorite. There were a lot of great races and memorable surprise performances that season. Plus the cars were pretty much the best that they have ever been. Perhaps 1991 was actually the peak when it comes to the cars, but as a season I don't think it was quite as exciting as 1990. I also like the turbo era, but I don't think the cars were ever more exciting than in 1989-1991. There was also great variety in technology as races were won with manual gearboxes & semi-automatic gearboxes and V8s, V10s & V12s.
Perhaps also the improving TV production helped showcase the cars of that era better, as 1989 was the first season when onboard cameras became a regular fixture, whereas in the turbo era onboard footage was a lot more random. There's something very visceral in the onboard images of that 1989-1991 era, with the heavy vibrations and screaming engine sounds. I think 1989 Hockenheim is my all time favorite race when it comes to TV production, the broadcast sound quality is unusually good for that time. Listening to the V10 Hondas and V12 Ferraris reverberating in the trees with the sparks flying is just something else. Also the onboard cameras in the Ferraris were taken great advantage of in that race.
It's a shame how the 1990 Championship was decided, but that also makes it a more memorable and dramatic season. How Senna kept his Championship and didn't receive a long ban will always remain as one of the great mysteries of life. Funnily, in the 1990 Adelaide qualifying broadcast James Hunt actually blames Prost for the crash and calls him a whiner! It was a different world back then.
It has to be noted that Hunt really loved Senna in his final years. It's interesting because up until 1990 Hunt could actually be quite critical and fascinating in his commentary of Senna. But from Suzuka 1990 onwards he always seemed to turn the blind eye whenever Senna did something sketchy on track. I also love Senna, but for a TV commentator it would be good if some level of objectivity could be retained. Still, blind Senna love and blind Patrese hate aside, the greatest commentator of all time.
Speaking of Senna, if you're a fan, I highly recommend revisiting 1992 Kyalami. It might seem like an oddball choice as it's a race where pretty much nothing at all happens, but it's now one of my favorite Senna performances and favorite races of all time. And it's all down to the TV production.
The South African producer took great advantage of Senna's onboard camera and long periods of time are spent in Senna's car as he heroically chases down Patrese with his outdated McLaren, equipped with a manual gearbox. In that race you can see Senna hitting all the apexes with millimetre precision as he does everything he can to keep in touch with Patrese, who is clearly driving a vastly superior car, but also clearly lacking the precision of Senna in his driving. Add the V12 Honda engine sound and fabulous image vibrations to that and you're in seventh heaven. It's also the race where Hunt infamously spends most of the race talking about Patrese and why Williams should sack him.
Also, as mentioned before, 1985 is a really great season from the turbo era. 1986 is the one people tend to talk about, but for me 1985 is the best season of the turbo era.