Most ppl will go for undermount as it is easier to clean ur table top. I would say 90% of my customers install their kitchen sinks either top mount sinks or undermount sinks as undermount.

An Undermount sink can be installed as top mount but most of the undermount sinks in the market cant be installed as top mount. You just nd to look underneath the sink, if they have clips to secure the sink to your table top, then it can be installed as top mount.