SR is much better than SCR. I've seen many trains from Chennai like chennai allepy, Chennai Trivandrum etc are well maintained, may be they're short duration, that might be the reason...
Nellore to vijayawada distance is 277 kms and I'm not just making a thing, since it is day time on both the ways and 277 kms with out any stop on day time is considerable fact. Since you are from kerala you don't know the situation, as kerala is terminating or starting point for all the trains, there won't be much crowd at day time, but that is not the case in A.P, sorry I didn't mean and kerala is like my second home, I am just saying my opinion, that's...
more... it, and any way neither you nor me are deciding the stops,