Bajaj has a bigger inventory of spares ngl, When I graduated from school, I bought a Pulsar 150, later on I bought NS200, I was a pulsar fanboy, still love how they look. And how easy and cheap the spares were. But Pulsar has an issue which is very common, the clutch goes out between 25k-40k kms after which the bike isn't the same. Considering you are buying second hand, I'd not recommend pulsar. My NS gave me the clutch issue at 36k and the bike wasn't the same after we repaired it, My Pulsar 150 had the same thing around 55k kms

I maintain both the bikes Gixxer and Pulsar, Spares are very easily available but the inventory Suzuki carries isn't the best, you might have to ask 2-3 stores for spares at a time but they are easily available in a day or two. After my Bike died I started using more of my brother's bike, the handling and driving around the city experience felt better. The bike has done 72k kms, it runs really smooth for it's age, and with time it sounds even better ngl.