I have a couple of coworkers with new Transits, mine is not here yet.
The standard 3.7 is adequate but not speedy, it is slower than a GVan with a 5.3 but much better than a GVan with a 4.3.
They are also not that fuel efficient though that could widely vary by configuration since they come in several wheelbases, 3 different roofs and from 150 to 350 series.
If it has windows, budget for window tint if you need the air to work sitting still.
Overall my coworkers love them, the few niggles are far outweighed by the nice comfortable ride and drive and other features that make them well suited to what we do.
If I were buying I'd get an eco-boost or diesel.