I did a Spring over on my YJ quite a few years back. When I did it, I angled the rear axle up a bit and made a home made 1" transfer case drop and I didn't have driveline vibes.
I have done several setups on leaf sprung Jeeps (CJ's and YJ's) and there are some really nice setups SUA that worked really well, (the monoleaf setup, deavers, etc) but were pretty expensive. A cheap lift kit on a YJ will always ride rough and wont flex much. For cheap, the SOA in my oppinion is the way to go on a YJ, lots of flex and they ride pretty well. But you have to put your research into the setup. Leaf spring selection, shackle location, anti wrap bar, axle caster, and shock selection and different combinations will all heavily effect whether it's a good setup or a deathtrap on wheels.
That being said you will have to have an antiwrap setup of some kind or you will have really bad axle wrap and break drivelines. And it is hard to beat coil suspensions, which is why I have a TJ now.
To be honest the driveline vibration should be the last thing you are worrying about if your doing a SOA.