Desert use (going fast, jumping, etc.) is where modded beams really shine. Their clearance helps a lot in mud & snow too, so I'd say go for it if those are your primary intended uses.
Crawling (climbing while sidehilling especially) is where modded beams can potentially get you into some trouble though. With the pivot mounted up higher in the chassis, the tendency for the suspension to jack is increased. You also have much more narrowing of the track width when the suspension unloads while climbing a steep hill. For these uses I would recommend keeping the beams stock and instead use a good set of beefy drop brackets (such as Skyjacker's or James Duff's). Your axle being wider will to a small extent offset these drawbacks however.