I did do a quick search and there are many opinions as to which is the better bag, so it really depends on the individual. Some points to consider:
-Velo will be a little heavier than the City or Town.
-Is cross body important to you? (I don't wear cross body but when I double the strap on the Velo it works perfectly on the shoulder for me).
-How much do you carry? Both the Velo and the Town have more height but the Velo carries more.
-Do you prefer north/south or east/west? Both the Velo and the Town are more north/south and less east/west than the City.
In one of the threads someone mentioned that with the Town things were kind of stacked on top of each other. The Velo is a "throw everything in" type of bag. Keep in mind too that the older Velos didn't have an adjustable strap. Not sure what year the change was, I want to say around 2012, my 2010 doesn't adjust but my 2013 does. Might be the same for the Town?
If you go to advanced search, then under "search threads, and play with your keywords ("Velo vs City" for instance, or "compare Town and City"), then search the Bal forum, you'll find lots of opinions. Here's one thread for example:
https://forum.purseblog.com/threads/velo-vs-city.732139/
This might help too:
https://www.yoogiscloset.com/balenciaga/guide