I've done the trip a couple of times. If you're on your own and haven't got a fractious Mrs or kids to worry about it's OK. But, it can add between 6 and 8 hours to your journey, so you've got to decide whether the money's worth it.
If you're arriving on a night-flight there's a pretty good chance that you'll miss the last bus out of Antalya and will be at least a couple of hours too early for the first bus. Mind you, the benches at the Otogar are reasonably comfortable to sleep on.