My home inspector called this a split bus panel and that it should be replaced eventually. Looking at split bus examples, I don't think it is. Was he just confused by the 200Amp double pole braker? Should I have this updated?
It's not a split-bus/Rule of Six panel.
I plainly see a huge main breaker. The distinguishing feature of a split-bus panel, also called a Rule of Six panel, is no main breaker.
The entire point of a split-bus panel was to allow services > 60 amps so you could have all-electric houses... but avoid the (then, very expensive) cost of >60A breakers. The strategy was to place the large 20-50A 240V electric appliance loads in the "main" or "Rule of Six" area, along with a 60A breaker which would power an internal subpanel. In this subpanel went all your 120V loads.
Honestly I think what confused your inspector was the cluster of breakers that is 5 spaces tall x 2 wide, with a large empty section above. I had to do a double-take myself. It looks a lot like the 4x2 or 6x2 group of "main breakers" section of a split-bus panel.
Looks OK to me
I wouldn't replace the panel on the basis of it (not) being a split-bus panel. It's a GE Q-line with all the spaces enabled for the double-stuff breakers, so you could fit 40 breakers in here if you didn't need GFCI or AFCI. And if you do, there's just enough spaces to convert them all. And GE makes a magic 1-pole AFCI that can be used in pairs to protect 240V circuits.
The only reason I'd replace it is if the GE dealer (a local electrical supply house) were to say "I can't get you breakers for that panel". But I doubt that would be so.
No, not a split bus. That main breaker is a low-cost way of some mfrs attaining a 200A main using molded case breaker frames originally designed to only go to 100A; they essentially parallel 2 x 100A breakers and call it 200A. You and I can't do that in the field, but the manufacturers can if they can get them to past the proper testing and list them as such. These are a relatively new (15years?) development in the breaker / panel industry, so there are still lots of people who have never seen them and don't understand.
That is not a split buss panel. Those have several breakers for heavy loads (range, water heater, clothes dryer, HVAC) that are not controlled by a main breaker. There is a sub-main breaker for the other circuits. As long as there are 6 or fewer breakers, they are legal. I don't like them, but they are legal, or at least were legal, not sure if they are anymore now, but you are grandfathered in.
I see no reason to update. Looks like a good clean layout with plenty of additional spaces.