Done properly, a spring over axle conversion or a coilover conversion will both take a lot of work and money but the coilovers will cost more and probably take more work to install. I would figure out what you want to do and do it. Don't settle on leafs because they're cheaper or coils because they're better, do what you want so you don't kick yourself in the *** for listening to other folk. Because when it comes to actually getting out and wheeling it, not comparing numbers with guys online, as long as you drive your truck into and out of the woods it doesn't matter if you go with coils or leafs.
A coil sprung suspension will generally provide a technically better suspension than a leaf spring in terms of flex and comfort, but I prefer the leaf springs because they are simple, reliable and tough. All you need to worry about is setting your pinion angle and installing springs. Leaf springs will bend, snap, pivot, whatever and still work until you can fix or replace the part. On most occasions, when a main leaf snaps, the vehicle will be held up by the rest of the suspension and allow you to limp home or at least get out of the woods.
The idea of SOA is that you're gaining lift height by relocating the spring mounts instead of relying on a heavily arched spring so most people will run either a stock height or small lift spring. 0" lift, 1-1/2", 2", 2-1/2".
With your price range I would stick to leafs. You will need a high steer setup, all new spring perches and u bolts, rear anti wrap bar, new shock mounts, extended brake lines and whatever else I forgot. You can probably set it up yourself for 1,500 but if you're buying everything and paying someone to install it you will need to save up more bones. You will most likely spend close to that on parts either way.
2 door loveThe U.S. Army vaguely envisioned something bigger than a motorcycle, smaller than a truck, and undaunted by the most difficult terrain.