I had a very hard time picking between Norton and Trend Micro. I picked Norton because it includes a firewall. A good one at that. Firewall boosters aren't my cup of tea. I give favor to McAfee for only one reason. Fully offline signatures. I want those babies running in memory, not constantly using my internet connection which slows things down more than speeding them up.
Low RAM usage does NOT mean better performance... In case of McAfee, it's RAM usage is ok but it slows the system down. On Windows 8 it killed my boot and it will not allow me to add exclusions to FP's without turning off the AV (it will continuously delete them). Trend Micro and Norton are mostly cloud based but I clearly see Norton downloading something on updates so it probably does have offline protection of some kind. I haven't used Trend Micro that often to give an educated guess on it. Trend Micro has the best detection out of the 3 here and might have the best zero day also however Norton is getting much better than it used to be. Ashamed it won't let me tell it what to do on everything it finds (unless it can which by all means, someone let me know).
Since I like to balance performance and detection capabilities and also have access to more settings, including being able to be asked what to do with a file (not just delete/quarantine - not having the ability to add exclusions along with these options is useless) that it detects, I pick Norton. It gives that balance I need and much more control than the other two combined.
Norton has no affect on the performance of my computer. Trend Micro affects browsing speed, and McAfee slows everything down. I think I covered everything.
Note: This is from personal experience. Not everyone will experience the same. Remember this in case you disagree.
Two programs from Trend Micro and Norton are been witnessed from their poor track records before,as technology techniques are not emerged but today's generation are both at nearly excellent stageand holds purely from cloud.
So pick your choice between TM and Norton but for McAfee well still inconsistent from its performance.