I say absolutely cheaper. Some people will say it is cheaper and easier for a chevy swap because there are no aftermarket parts for the magnum swap, but no way. Especially if you are doing the fab work/welding yourself. All the chevy stuff you can buy, but it adds up.
Pros for Magnum swap vs Chevy swap
1. Fuel system - No change, 4.0 fuel pump will feed the 5.9 and all fuel connections are the same. Unplugged the 4.0 fuel line at the frame and plug in the 5.9 line (you can see the fuel line hanging in my transmission crossmember picture). Chevy would require different fuel pressure/pump maybe connectors/lines, not sure.
2. Electrical - As long as the new PCM is the same buse (mine is CCD), its fairly easy. Yes you have to dig through the service manuals and figure out what wires to splice together, but they are almost the same inputs outputs and the dodge PCM will run the jeep guages. Chevy, you would need aftermarket guages or the ones from a donor truck.
3. No adapter for the transfer case to transmission. I already had a SYE, and was able to keep my transfer case. Adapter for the chevy is about $500 easy and then more work to change input/output shaft to match each other.
4. I used advance adapters universal mopar motor mounts and modified them. Once I pull the motor the final time, I will post pictures. Probably could have made them myself.
5. I did buy a custom aluminum radiator and triple fan kit, but the stock one is not going to cool any V-8, so no way around that unless I modified the radiator support for a ram/grand cherokee radiator to fit, but the XJs just don't have much room for a larger radiator. I didn't want to skimp on cooling.
6. I haven't worked out all the little details for instance the shifter bracket will have to be modified, it is a cable shifter so just finding the right spot to mount the bracket should be easy. The transfer case is about 3 inches forward from original location, but for shifter, just modify the bracket and drill a hole 3 inches back for the new pivot point the shift linkage should have that much adjustment in it.
I bought a 70k super clean motor (2001) for $600 and a complete running 140K 4x4 truck (2001) with a spun bearing for $600. Spent about $700 on the radiator, custom shroud, and triple fans. 170ish on the motor mounts. I have about 2K into it, But Still have a whole parts truck to sell and the good drivetrain that came out of the jeep. I could have saved on the radiator, but did go with a high end griffin aluminum. I will actually still meet California emissions too.
Will keep everyone posted on the progress.