Best Manual Transmission You Have Driven???

I have all three. There's something special about the gated 360 spider, it just feels right and makes me smile every time I drive it. I'm taking it out tomorrow. The 430 revs pretty quick in comparison and requires quicker shifts. The 550 Barchetta is smooth and being a GT it's more of a cruiser that challenges you to keep it from speeding too much.
When I was 17 I had a '76 Triumph Spitfire and I fell in love with manual transmission convertible sportscars. I've been chasing the way that car made me feel ever since.

 

550 with the shift rod without a doubt. That cable stuff just doesn’t cut it

 

Always partial to the 355 but..

The smoothest and quickest gearbox I ever rowed was in my former peugeot 405 mi16, it was so good.

 

2003 Jaguar S-Type . . . it uses the Getrag model 221, which is a modified version of the model 220 used in BMW 3-series cars. Smooth, precise, positive, and the shift lever is perfectly placed and weighted. It transforms the S-Type.

 

FWIW, it was an old Toyota Tercel hatchback that we bought for ~$1,200 for our oldest son as his first car some 20 years ago. It was high mileage and we took it for a test drive during which I was amazed at how good the shift was.
Second best is the '18 Mazda 3 manual that we own as my wife's car. It is just about as smooth and easy. My '07 Cayman is very close.

 

I know the original Acura NSX was rated as one of the best. I thought it was good, but never stood out to me in any meaningful way..