I tested a Discover 100 DTS Si myself, and these were some of my observations:
1. Low end torque alongwith the low weight created an excellent feeling all-together, in city riding. The 1st gear startup from signal will be great for the owners...
2. The 5th gear was very useful in the city, with the bike picking up cleanly from speeds as low as 25 kmph (speedo). (Solo, no pillion)
3. From Low end to midrange, the smoothness was worth applauding. Upto 50 kmph in top gear, no complaints.
4. Suspension was smooth, somewhat the same as Platina.
5. The bike impressed me. From all the 4 stroke 100cc's I ever tested (Passion, Centra, Discover, Splendor and Platina) I would gladly choose Discover only, based on the city ride comfort... (Although, I didn't test Honda Twister as yet!).
However, After Sales Service might be the reason one might differ... Anyways Bajaj Auto, Best of Luck with the Sales.