MSE is solid, quiet and does the job.
Little slow on scanning, but not so you'd notice.
When installed, the only tweaks you should do is
- get it to scan daily, rather than weekly, and
- get it to do it at a time you are usually on the computer, and
- enable it to scan removable drives (Settings->Advanced)
Keep it updated, be careful with emails and links and you should be fine. But nothing (even the most expensive/best) is guaranteed...