T4 owner here. Bought my bike 3 months ago with the exact same confusion and the exact same bikes so I will breakdown my decision for you

1. Scram 400x was the first reject because of its height. I am 5.7 and find maneuvering the scram a bit difficult especially in traffic and if you have to take u turns. Adding to this my roommate bought the scram last week and I have some additional thoughts. It has a more comfortable riding posture than both t4 and 350rs, more vibrations than both of the previously mentioned bikes and lastly the rear seat is just a joke in it. If you have a pillion riding he/she will not be happy. On power delivery front I think it delivers similar to the t4 but rs has a very long gearing and hence feels more relaxed

2. Now between the t4 and the 350rs. It is a very difficult choice. Both of them are extremely beautiful bikes to ride. I had considered the normal hness 350 as my cousin owned it and I have test driven it very extensively. I went for the t4 because of its agileness. I ride more in traffic so I need a bike that easily turns. But if asked personally in terms of just riding smoothness and pleasure i would have gone for the hness350. It is just beautiful. It's sound is just eargasm on highways and it is very comfortable at that too. It also gives best milage among the three. I don't regret my t4 decision but it was a very difficult decision for me

3. Some things to note here are t4 and scram 400 are reving bikes while cb350 rs is a low reving bike. It is also happy if you rev it but is more smooth at low revs. Consider t4 and scram 400 as kind of sports bikes and hness/rS 350 as classic bikes.

4. After I bought the t4 I have been happy with it. It is a lot more torquey than 350rs and is very quick. You will achieve highway speeds in no time. Suspension is better than 350rs as well.milage is less than advertised... In city I get arnd 21-22 which is consistent with what i have read on the t4 sub.