Lift springs are probably easier and cheaper. The springover itself isn't that expensive or time consuming, but there are a lot of other things that should be done to do it right that boost the cost, time, and effort - longer shocks and fabrication of new shock mounts, relocation of hard brake lines and/or installation of longer flexible brake lines, new or lengthened driveshafts (possibly with CV joint(s)), twisting the front axle to add caster and to reduce the driveline angle, fabrication of new bump stops, etc. There is also a long list of things that are convenient to replace/upgrade while you're in the neighborhood (spring bushings, u-bolts, etc.) that can boost the cost of the overall operation. I ended up with about 6 1/2" of lift keeping the original springs. If ride were a primary concern I would not have done the springover (this is primarily a trail truck), but I am happy with the ride (though I've twisted the front axle to add caster, replaced all spring bushings, body mount bushings, etc.). I'm very happy with my springover. IMHO, I think a springover (done right) is superior for a truck that is primarily a trail truck, and will be used on difficult trails. For a truck that is used for commuting or primarily on-road, lift springs are probably a better solution.
Hope that helps.