Eset Internet Security followed closely by Kaspersky Internet Security.
Kaspersky wins on protection, both by objective and subjective reasons. Objectively because its detection engine is probably unparalleled, combined with KSN and regular signature updates, it's hard to match. Subjectively because it's been on the top for such a long time among its competitors that you just "know" it's a good product, and you can't say the same about most other AV suites due to either weaker protection results or bad behavior from the vendors. Kaspersky's been consistent on what it does for several years. Although, I have to say I'm worried about its future with everything going on recently. Loosing market share and access to other resources like bug bounty programs is bound to affect it somehow, so the following months will be critical to evaluate if it remains as good as it is today.
What I don't like about Kaspersky is that it tries to shove components down your throat you didn't ask for. Password manager is opt-out during installation, and it attempts to reinstall itself after each major software update, which I consider bad behavior from Kaspersky. But the worst offender is the VPN module, which cannot be opted-out from installing unless you manage to download the offline install files and forcefully remove the VPN installation files. This is the heart of the issue I have with Kaspersky, as it feels like dirty move from a shady company when it doesn't give you a choice on the matter. They could easily address this, but it seems they are not interested.
Eset Internet Security wins on trouble-free usage and performance, though. I mention EIS instead of ESSP because, with the exception of LiveGuard, everything else on that product is useless to me. Eset is honest on what it offers, never attempting to shove unnecessary features upon install, and being fully configurable. You can easily grab the offline installers (I just don't like web installers for anything), there's no offerings of other stuff upon install, and throughout the years it has remained consistently good. I also like how it sits quietly and never bothers you. The performance impact is possibly still its greatest strength compared to every other AV. Also, you can get actual support for it and Eset's knowledge base is possibly among the best. Still, it often fails on achieving perfect scores on tests due to the lack of a behavioral scanner, which is Eset's greatest weakness, but their signatures are probably the best available and compensate for that.