Is this a split bus electrical panel?
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.