The best? Hands down - Prophet/RCS. The question is whether or not your budget can afford it.
There's a lot of stations I know of who avoid the whole internet voice tracking issue and have the jocks simply record/e-mail MP3s to the station, then place them in the automation system and set sec tones to hit the talkover posts. Saves a LOT of hassle.
I know Simian is panned by many here, but BSI has a nice way of handling VTs by using the intro & sec tone settings and their free InfoEdit program allows the jocks to set the tones so they play back perfectly in Simian.