In great shape at the moment (2018) I don't think there is a poor seat in the room and the sound is pretty damn good from all of them. Lovely staff now (it hasn't always been the case) and a great place to go to see a gig.
Upstairs is a great place to be too, worth a visit in its own right.
There's no downside to Ronnie Scott's, with the possible exception of the food not being tremendous, but that's traditional:
'You eating here? Got the soup? Indians come from miles around just to dip their arrows in that...'
That was Buddy Rich as heard by me live @ Ronnie Scott's Club in 1981.
The food is pretty good these days, I usually get the fish pie with a portion of fries on the side. Maybe with an additional portion of fries as a chaser, if it's been a long day. The staff are focused and service is better than most restaurants.
Unfortunately there just aren't that many jazz venues in London, so getting tickets can be a challenge and costly when it's someone super-popular.
Oh yes and most important:
Ronnie's completely stops that stupid 'oh i must film this gig with my stupid phone' behaviour. It also completely stops that 'oh I must completely ignore the musicians and talk loudly about myself' nonsese that happens in pretty much every other London venue, large and small.
This all adds weight to Ronnie Scott's being one of the best serious London music venues. Long may it continue.