Depends on the car if you need to remove the sub frame and how bad it is. My 89 oldsmobile, it was pretty difficult getting the sub frame out to get the trans out. On my 96 saab, it was cake, and pretty easy. My 02 Jetta hasn't been too bad either.
If you use a hoist to hold your engine in place, you may need to get it all done in one day, I know I wouldn't trust a hydraulic jack/hoist to hold my engine in place for a long period of time.
I have one of those support bars, they work great. Right now it is holding my engine up in my jetta while i'm waiting on another part to arrive to finish my clutch job.
In this picture only the mounts on the passenger side are removed, and the trans is not in the car. so the bar is holding one side of the motor while the other side is secured by the mount. I got mine from NorthernTool online because the Harbor Freight one was on some long back order. It has really been a great investment, especially if you like doing a lot of your own work on your cars and need to drop a trans.