The requirements were really simple: runs on Mavericks, real time scanning on file access including compressed files, checks for Windows virii, and scans email messages (and attachments).
With those simple criteria the answer for me was either Avira or McAfee.
Here is some of the data.
| Make | Gut | OSX | Real | Windows | Email scan? | Lic | Thoughts |
|---|---|---|---|---|---|---|---|
| feel? | 10.9 | Time | virus | ||||
| Scan | |||||||
| Avira | Nice | Yes | Yes | Yes | Yes | Zero | |
| McAfee | OK | Yes | Yes | Yes | Yes | $ | Corps like. |
| Sophos | Nice | Yes | Yes | Yes | No | Zero | |
| Avast | Nice | Yes | Yes | No | Yes | Zero | No Win. |
| ClamXav | Nice | Yes | No | Yes | No | OSS | No RTFS. |
| eScan | Nice | Yes? | Yes | No | No | $ | No Win. |
| Norton | OK | Yes | Yes | ? | Yes | Unknown Win. | |
| F-Secure | Nice | Yes | Yes? | ? | ? | $ | Do the basics?! |
| Kapersky | OK | No | Yes | Yes | Yes | $ | No 10.9 |
| Comodo | OK | No | No 10.9 | ||||
| ESET | No | Do the basics? | |||||
| MacKeeper | No | Suspicious | |||||
| Virex | No | In beta. |